I have quite a few people I have on my favorite sellers list, people I have bought from before with good results. I get an email here and there with a link to favorites top picks. I will seldom GO to ebay at all unless I am linked from this email these days. The link takes you to their top picks but of course you can link to sellers other offerings and browse. This is a pretty good feature as well...So I noticed that the sellers I go to most are sellers that dont offer thousands of coins at a time... Its a shame because I end up not looking at some sellers much even if they have a good selection and wide variety...they just have many thousands of coins and you could spend all day. I dont want to spend my whole time going through one guys stuff...there are sellers like AAC who have a HUGE amount of LRB, 99% of which I dont want, maybe if I am lucky, a coin of two will stand out but I just dont want to go through all those coins...searching doesn't help narrow it down more when you are just looking for a real nice coin of any ancient period. I tend to go to the people that might have a few hundred or less...Then I can look at the best of many sellers instead of spend all day going through page after page of Constantine coins.
I stopped buying on ebay for many reasons: the difficulty of finding items based on the infinite variety of ways to classify things and the tendency for irrational exuberance to inflate prices well beyond their worth (this is true especially for bullion - I've seen bids on 1/20 gold in the $70 - $80 range; eeek!). Not to mention the large risk of fraud: I had to demand a refund after receiving a coin that looked like a blue marlin had rammed it underwater. The picture on the auction page of course looked pristine. Rrgh. I have had good luck selling there, though... so far, at least...
Oh, I have had little problem buying things on ebay...I get some good deals there and have trusted sellers.
