After having used st as my main terminal for a while now:

• Most things work just like in xiate, but I did patch st heavily. Took quite some time to do this, but it was also fun, so it was worth it.
  
• st uses much less memory than xiate (12-20 MB for st, 40 MB+ for xiate) – but way more CPU time. 😅 When I move another window on top of an st window (so that st has to do a lot of redraws), the CPU spikes so much that my whole X server begins to stutter.
  
• There’s no point in denying it: Font rendering is way better in xiate, because it can use the whole GTK-Pango-Whatever stuff. That’s a lot of code and could arguably be viewed as “bloat”, but the results are also better. Font stuff is not trivial, it’s inherently complex.