The official product page can be found on the Asus main website and ROG website. All the information you need is there.
http://www.asus.com/uk/Monitors/ROG-SWIFT-PG348Q/
or
http://www.asus.com/ROG-Republic-Of-Gamers/ROG-SWIFT-PG348Q/
User manual is here :-
http://dlcdnet.asus.com/pub/ASUS/LCD%20Monitors/PG348/PG348Q_English.pdf
More info can be found by clicking on the specifications tab at the top..
Its an overclock like the X34, and Asus are recommending a 980Ti to get the 100hz. So older gen cards or lower spec cards, you will probably be needing an SLI set-up.
The Acer and Asus are almost identical in specs, but there are a few little differences, like HDMI 3440x 1440 is 50hz in the Asus compared to 30hz on the Acer, and The Asus has both Flicker free & ultra low blue light TUV certification. Plus improved heatsink and convection airflow to keep the monitor cool on long gaming sessions. But it mainly comes down to aesthetics, which monitor you like the look of the most. Personally I hate glossy black plastic! So would go for the PG348q
Everyone's hoping that the delay in Asus launching the PG348Q is to iron out all the problems the X34 had at launch, but until there are some reviews and most importantly customer reviews of this monitor, I would hold off..
Expected date in the UK is 12th February.
You also have to consider that Acer and Asus are trying to push the old DP 1.2 to its limits with these monitors but at a premium price. With the next gen of GPU's around the corner supporting DP 1.3, and true 144hz 3440 x 1440 panels over DP 1.3 announced later this year, it might be worth holding onto your cash for something more future proof.
Beautiful looking monitors though, very tempting..