Coming from the Zero, Hien Soft, Matrova BalanceX PU Soft and Vein PU Mid, I'm really liking the speed of the KEY 83 Mid. It's a little slower than the Hien, has similar low initial friction, and doesn't sacrifice much stopping power in return.
Overall, I genuinely think the KEY 83 Mid is a great all-rounder. If you play a variety of games or spend a lot of time grinding Kovaaks, it's hard to go wrong with this pad. It offers a really nice balance of speed, control and feedback without feeling too specialized.
I've also seen people compare the KEY 83 to glass pads quite often. I haven't actually tried a glass pad myself, so I can't really comment on how similar they feel or make any comparisons there.