AOC AGON AG271QG 27" 2560 X 1440 IPS G-SYNC 165Hz - has good reviews and is an IPS panel.
I've used Dell Utrasharp IPS screens for as long as I can remember - I had the exact same 2 Dell Ultrasharps you're replacing but was boring and replaced them with 2 x Dell Ultrasharp U2715H.
As has been mentioned already, quality TN panel's colours are so much better than they used to be, when calibrated correctly. However, if you're use to the viewing angles and the softer sheen of an IPS panel you may find the jump to to a large TN panel difficult to adjust to. This will be especially difficult if you will using the panel for work: spread sheets, word, coding etc when not gaming.
If you're after pure gaming panel then the Dell TN is great - i specced one for friends rig and was very impressed. But, out of curiosity i played around with some spreadsheets, Word and CoffeeCup and couldn't get comfortable with the relative screen glare when compared to my Ultrasharps (All relative though - i know). Gaming however was a different experience altogether - I could still tell it was a TN panel but I wasn't bothered as this wasn't as obtrusive as when using solely as an office panel.
I mention this as you'll be swapping from 2 quality IPS panels, which you've had a number of years(?) and you may find the panel transition a bit underwhelming for desktop work - maybe. I really recommend that you try and test one in a shop - if possible- as you may prefer the compromise of an IPS Gsync - purely for the desktop/app usage if you find yourself in that environment more often than not.
But if gaming is your main intended use - then the DELL TN is a great panel and you can probably ignore most of the above