The only lag I experience is when opening the store and hitting the search button. I start typing 4-5 letters, it gets the first one and after a couple of seconds the others appear. Other than that it's all good.
I experience a bit of lag a few days ago when I was toggling between my pictures. I noticed it wasn't very fast and kept getting stuck for a few seconds
Ehhh rarely sometimes my typing input will lag and then catch up with what i put.. but its rare... love my 8x is smooth and the os is to thx as well.. (T-mobile version so no updates like the international models) want the update to stop it rebooting thats the only thing i dont like, if it does it will happen like 3 times a day... but the phones fast to boot right back up haha
No lag here either. Everything is super smooth. The only noticeable bit of lag is when typing in the IE search bar, the suggestions as I type are a bit slow.