Purchased both to compare, kept the Asus PG348Q because my copy had lower backlight bleed and a far superior UI and calibration than the Acer I bought.
I've since used my EyeOne color calibrator on it to further tweak, but still find the Asus to be slightly better. If they're the same price (and they were for me), I would go with the Asus. FWIW, they're essentially the same other than UI and stock calibration modes, and I actually prefer the stand of the Acer. The Asus UI is just too good though, as is the stock sRGB profile for those without calibration tools.
I've since used my EyeOne color calibrator on it to further tweak, but still find the Asus to be slightly better. If they're the same price (and they were for me), I would go with the Asus. FWIW, they're essentially the same other than UI and stock calibration modes, and I actually prefer the stand of the Acer. The Asus UI is just too good though, as is the stock sRGB profile for those without calibration tools.