I can echo many here in that the issue of the Papacy was a big factor when I began seriously exploring Eastern Orthodoxy 7-8 years ago after briefly considering the RCC. In my case, there may have been an anti-RCC bias at play, because in my Southern Baptist days I owned such books as "A Woman Rides the Beast" (Hunt) and "Two Babylons" (Hislop). However, when I began questioning the Baptist distinctives I grew up with (ie Once-saved-always saved; Zwinglian memorialism, believers-only baptism) after reading some of the church fathers, I actually wanted to give Rome a fair shake, since it was reading some of the RC apologists' arguments on certain topics (in response to the obnoxiously Calvinist James White) that convinced me that much of what I thought about the RCC was incorrect.
At the end of the day, though I read such books as Ray's "Upon this Rock", I found the historical evidence for papal supremacy (let alone papal infallibility) lacking. Although it would have been much more convenient to go to the local RCC parish than to drive an hour away to the nearest EOC one, I couldn't in good conscience subscribe to papal infallibility. I sided with the East on the issue of the papacy and the filoque (plus I thought Rome over-dogmatized certain Marian beliefs). Ultimately, after even being an Eastern Orthodox catechumen for about 1-2 months, I didn't end up crossing the Bosphorus. However, on these particular issues that have divided East and West. I still side with the East, although I am definitely more western on certain other emphases.