Differences aren't as pronounced at the low end, but IPS does tend to be more desirable in a lot of areas. Almost anything in the $1000+ range is IPS. The technology itself was pioneered by Hitachi in the late 90s as a higher quality alternative to twisted nematic panel types. Given that you see very few PVA types now, most non-IPS variants, especially toward that price range, use TN panels. There are many details to a display, so you may want to check reviews on whatever you're about to purchase. If you can find anything in depth, that is even better. Saying one is better than the other is very generic, but all of the points regarding contrast ratios and viewing angles typically hold up.
I think I already mentioned this, but all displays age. These comparisons are only somewhat guaranteed to hold when comparing different models of relatively new displays.
