I've had both (and I no longer have either - Glocks just aren't aesthetically pleasing enough for me). They're really not similar at all, though - I think you need to either go back to the books or go physically compare the two models.
The G36 is considerably bigger than the G33. It's almost the size of the G32/23/19. It is flatter, though, but it's not nearly as small as the subcompacts.
The G33's muzzle blast was pretty amazing. The recoil isn't the problem, it's the concussion from the magnum-pressure round throwing that light bullet out the front superfast, along with the associated powder burning outside the short barrel. People would
always come over and ask what the heck I was shooting when I fired the G33 (I bought mine when they first came out in the mid-/late-'90s, so it attracted a lot of attention since no one had experienced the .357 SIG's blast before).
The G36 is very pleasant to shoot - much more so than a micro-compact 1911-type.
Both guns worked well. I had some issues with primer crud blowing back into the G33's striker channel under the high pressure of the .357 SIG rounds, which necessitated cleaning the striker channel (no big deal, but it's not part of standard maintenance acc. to Glock) every 200 rounds to prevent light strikes. The G33 fed like a dream - you're shoving a 9mm pole into a 10 mm hole.
Anyway, the ammo for the .357 SIG is more expensive - something else to consider.
Hopefully this has given you more to think about. Best of luck with your selection.