The Acer XR341CK is now in stock at NewEgg: http://www.newegg.com/Product/Product.aspx?Item=N82E16824106002. I just ordered one and will post my thoughts on it once I get it, hopefully this weekend.
I got home late last night and setup my new monitor early this morning. So far I am adjusting to the curve a a bit, however I am quite pleased with the panel so far. It took me about 30 minutes to configure the monitor settings to my liking.
First and foremost, there aren't any dead/stuck pixels which is what I generally worry about most when getting a new monitor. Second, Freesync is really nice - this is my first time seeing a Freesync display and it definitely works. I launched GTA5 and it looked amazing in ultrawide and even though I only get 40-60 fps on my 290x, there is no tearing and the gameplay feels very smooth. I tried a couple of other games (Diablo 3, Dota2, LoL, Crisis 3, Battlefield 4) and noticed that ultrawide worked for all but Dota 2, which doesn't support HUD scaling correctly.
I didn't buy this screen for gaming, as I generally don't have a lot of free time. I did buy this for productivity apps (ssh terminals, excel, sublimetext, etc) and it finally allows me to drop my second screen. I've always wanted to only have 1 display on my desk, and I think this should allow me to get away with it.
Overall, from brief experience so far, I hope ultrawide becomes more mainstream, as I really like the immersive feel when gaming plus the productivity benefits it allows. I'm looking to keep this monitor until they make a 2160p ultrawide (6720x2160) so here's to it it lasting a few years.
If anyone has any questions or wants me to test anything, let me know.
Oh and also to answer a question about the screen refresh rate, I definitely see it dropping to 30 and maxing at 75. I don't think it goes outside this range.