case question

They are neck and neck as far as pure performance numbers. If you game at 1440p, either card will provide all the overhead you'll need for several years to come. At 4K, they also perform similarly, able to modestly exceed 60fps in almost everything. There's no overhead there, but it's not needed unless you spend $1800 on a monitor.

The 1080 Ti should be ~$100 cheaper if you shop right. One main thing to consider is the Turing architecture (2080) has ray tracing technology and some Deep Learning Super Sampling (DLSS) capabilities built in. There are only 4 or 5 games that even take any advantage of that, and it remains to be seen how many over the next couple of years will bother.

Ray tracing is better than rasterization at portraying lighting effects realistically. DLSS smooths graphics in the same way as anti-aliasing, but better, and with less performance hit. For me, I'm rarely paying attention to these kinds of nuances while I'm trying to acheive my next objective, or just stay alive, lol.

It's a coin flip, with the 1080 Ti being the old vs the new.