You have to choose between two coins that can enter in your collection, and they have, more or less, the same price. One is of the highest rarity but in a very lower state, the other is a common one but in an exceptional state and with a very nice patina. In each case, you know that you'll have to wait a lot of years before to have the possibility to buy one of them. So, what kind of choice will you do and why ?
Rarity for the sake of rarity doesn't really interest me, and it's just not enough for a coin to be high grade to interest me either. I have extremely rare coins, uncommon coins, common coins, and coins ranging from F to AU. There has to be a combination of other elements to the coin, such as a connection a particular historical event I'm interested in, or superb style, or the coin is of a ruler or a city state I care about, or it was such a bargain that I would have been stupid to pass up on the coin.
I have several "rare" coins and some in top condition. To me, a coin has to speak to me upon regarding it. If my goal is to get a coin of each roman emperor, I will prefer a relatively common coin in better condition if it has some historical value rather than just getting something because it is rare. Of course, in the case of some emperors all of their coins are relatively "rare" so in that case I will make a sacrifice but only if other coins are not available at relatively reasonable prices.
Condition is everything. I have the 6th known coin of one variety. It is unlikely to buy me a T shirt let alone a house.
Obviously condition is going to have a big impact on the price of any coin. For example, this rare variety of a Galba quinarius will be lucky to sell for more than $150 on any given day because it looks like a truck ran over it. Had it been in XF condition it would probably fetch close to $1000 because of the combination of rarity and condition. So obviously I didn't buy it because of its quality. But I also didn't buy it because of its rarity. There had to have been one or two other factors for me to be interested in this coin. They were: 1) I think the portrait is nice despite the condition of the coin; and 2) I am interested in this time period and the individual portrayed in the coin, and 3) the price was right.
A coin need to tell a story for me, rarity or not. But, obviously, it's better when the coin is a very nice one, because it's an artistic proof of the past. For exemple, i'd like to have, one day, a coin of Cleopatra and/or of Cleopatra Selene, but if there is no pleasure to see it, i prefer to not buy it. About the choice, i choose to buy the nice one.
For me, state depends on rarity. If a coin is common enough to be available in high grades, I'll wait for a nice one. If it's prohibitively rare, I'll take what I can get. Some types are only available in VF and that's fine by me.
There is also the matter of which type of rarity we are considering and which kind of condition problems are present. Some coins are rare due to a small variation or unusual combination of dating devices. Other coins are rare and nothing like any more common coin. Flyspeck rare coins sell to specialists but tend to bore the rest so they do not bring big money. A major type linked to history or with beautiful die work can be forgiven little condition problems. I dislike rough surface coins must do not mind 'honest wear'. Others differ on that one. I paid $10 or the Septimius Severus coin below. Would you? Most would not have a coin that ugly for that price. Shortly before he died, Roger Bickford-Smith, the greatest expert in this specialty at that time, told me that of all my coins this is the one he would most like to have. He had never seen one. I have not seen another INVICTO IMP from the Alexandria mint but they are common from 'Emesa'. $10 may seem cheap for an 'only' but it is seriously overpriced for an ugly-as-sin coin of a very common emperor. The only place for such a coin at any price is in the collection of someone who cares.
The OP question is difficult for most of us to answer because there is so much more to consider. Condition and rarity are only two things. Style is often an important factor for me. In general I'd prefer a fine style coin in lesser condition to a pristine coin of ordinary or poor style, if the coin is relatively common. Doug raised many good points. I'll shell out big bucks for a rare or unusual coin, which for me generally means an unusual reverse. Oodles of nice portraits are available but a rare, unusual, or bizarre reverse makes me drool . I'm perfectly okay with lower condition for those types of coins. This does not mean I don't care about condition. It just depends on the coin. I love a fine style high grade coin as much as anyone (and have a few in my collection; see my avatar for one ), but for some types the grade isn't as important. My most recent coins-- yet to post because they warrant a big writeup and I haven't had time-- are in terrible condition but I'm thrilled to have them. They are scarce and none of them have ever been posted on CoinTalk.
It really depends on how rare the coin is, how rare the type is, and how much interest I have in it. If given the chance to buy the finest-known AnYang spade (most common spade type/variety), a 3-hole spade (rarest spade type) in crappy condition, or a rare-inscription spade (rare variety, common type) in crappy condition for the same price, I would most definitely go for the rare type (three-hole spade). Having the finest known is nice, but I am just as happy with lesser coins. I really have no interest in rare varieties because there are plenty of common coins for the type or rarer types I could pursue for the same cost. I don’t know when the rare type will be available again, regardless of variety. If only it was a US coin.
If it is a truly rare coin that I am interested in, I let rarity rather than condition guide me. I have several coins where there are only 2-3 known. In these cases I have accepted coins of lesser condition because I did not know if or when I would see one again. If the coin is not a type I am interested in I will not buy it regardless of how rare it is.
Location, location, location.... is the mantra for real estate and business owners alike.. for me the mantra is history, history, history... if I get that - then why not add a bit of style?? (to the level that I can afford of course)
I suppose considering only the two points from the initial question, I would probably go with state over rarity. I'm too much of a generalist in my ancient coin collecting so something common but of exceptionally fine style or grade would be more important to me than rarity. I'm like Sallent - rarity for the sake of rarity doesn't really do it for me, not to mention that rarities are very common with ancients.
For me it is a bit more complex. I do not buy lower grade coins simply because they are rare nor do I buy common coins simply because they are high grade. For me there has to be some underlying reason for me to purchase the coin. That reason can be a combination of historical importance, artistic merit, and how it would fit into the overall theme of my collection as well as how much I need to pay to get them. There are many types that I would like to own but have not bought simply because I felt that it did not meet what I felt I would need to be happy with it.
As a specialist, coins that are either rare or in good condition are equally alluring ... as are coins in fine style. Common coins are a must have for a specialist collection, if only to provide depth and context. Rarity is important, but not the end all or be all of a niche collection. And of course, fine style examples are supremely desirable, no matter the rarity! They are a perfect excuse for adding duplicates.
Depends. Are we talking about a ratty Gordian II versus a minty fresh Gordian III? Gordian II is a key coin to any Roman collection seeking all emperors, and is worth more as a cull than practically any Gordian III. Especially for someone who still gets shy at the idea of placing a $2,000 bid on a single coin. Now, if it comes down to two coins of the same person/place that would fill the same "spot", it's eye appeal all the way!
High state (minimal wear, centering, style, fabric, metal quality, surface, toning, roundness) is usually rare.
