The Dell UP3216Q is excellent, albeit a little over your budget. Also Asus ProArt PA329Q, but again, a little over budget.
The BenQ PD3200U is quite a bit cheaper but also very good.
I would look at 4K over UW. It offers more screen real estate and generally they are better panels. I've just made that switch myself from an X34 to 32" 4K and am really liking it. I wouldn't bother with 27" 4K though, it's just too small.
There's also the 38" LG 38UC99 and 38WK95C which are also worth a look.