I certainly looked at a One X and, when I realized the price advantage, considered it very seriously.
I thought the screen was good, but still suffering from color shift much the same as a low-end 23" IPS monitor. That's not an issue, but it shows that contrary to some of the drooling going on, it's not a gift from god or anything. On my second and third viewing, I felt that it mainly looked good because it was bright - and most phone displays are dim. The Galaxy Nexus AMOLED display in particular is very dim.
The thing is, outside the showroom and away from the spotlights, a really bright display one foot from your eyes doesn't seem like such a great idea after all.
Also, GSMArena's sunlit contrast tests still give the nod to AMOLED displays such as the S3's, despite the very high measured brightness of the IPS panel on the One X.
I have deteriorating eyesight and need objects to be more brightly lit, but the S3 display is already brighter than previous AMOLED displays, yet has less glare than the One X IPS display (that's a characteristic of AMOLED BTW). So personally, I prefer the S3, but most people would be equally happy with either.
