I'm sure that the game will be fine on Playstation 4, at least after a patch or 2. From what I hear, Skyrim was painfully buggy on PS4 at launch, but after a while was just fine.
With that said, Bethesda has a long history with Xbox. They made their console debut with Morrowind on Xbox, which never came to Playstation. Oblivion came to Xbox 360 a long time before it came to PS3 (don't quote me, but it may have even been a year). Fallout 3 had timed DLC exclusivity on 360, and Skyrim's DLC took insanely long to make it onto PS3, to the extent that fans were very angry. Now, mods are coming to Xbox One before they "hope" to get them on Playstation. Furthermore, without outwardly stating it, many of the devs such as Pete Hines and Todd Howard seem to play on Xbox by default. You'll notice that the E3 presentation was played on what appeared to be an Xbox One, or at least with an Xbox One controller (hence the control scheme icons).
The point I'm trying to make is it seems that Bethesda Game Studios' games are generally optimized for Xbox. If you ask me, the Xbox version is the paramount of their development, but that's just how it seems to me. Nothing against Playstation; seems like they're getting the best version of Metal Gear Solid V, so it's even
Rule of thumb: if you happen to have both consoles, I definitely advise that you go with the Xbox version. But I doubt the PS4 version will be that much different.