Enter is going to be the biggest keycap at 1.75u. You get a little wobble (box/dustproof switches can help some), but nothing structurally problematic. Most boards only start with stabs at 2u.
I'm currently using this one's FRL ancestor, and the only real issue I have is that it uses a 1U LShift with another 1u between it and the 'Z' key (kinda ISO-ish), and I just can't quite get 100% used to it, hence the "tombstone" layout on the new build.