Buy Anacs and sell pcgs and ngc . Anacs is cheaper and runs specials on some of the commons which may be good for Ike’s since they generally are low resale . Honestly I think Anacs is as tough as any of them and send most my commons I want slabbed there and some I want attributed . They are also cheaper to buy .
From what I’ve read here on the forums PCGS gets the highest premiums but NGC is so close that whichever is cheaper between the two you should go for. I like PCGS for US Coins and NGC for Ancients. I don’t know if PCGS even does ancients.
Its just demand that drives PCGS’s market value. They are well known and reputable. Honestly though NGC in my opinion is really just as good and respectable. If I could buy the same coin for even $1 less in an NGC slab than a PCGS slab I would do it. For example I have Morgan Dollars in both PCGS & NGC slabs and my NGC MS63s are all just as good as my PCGS 63s. However if you find a coin in one of the old school OG PCGS holders those can net a premium due to the belief that coins slabbed in those days were undergraded due to “tougher” standards back then.
For me, I prefer PCGS for American coins, and NGC for foreign and ancient coins. Actually I prefer most of my British and Imperial Roman coins raw in most cases, but if it's slabbed, I've found NGC to be better.