Limbing felled birches mostly, in my case - tophandles is absolutely no-go for that application.....
It really depends on the size of the trees, my most usual limbing set-up is the MS361 with a 8-pin 3/8 and 15" bar, but then there are areas with smaller trees, and times where I rather grab another saw, than change the set-up on the 361.....:biggrinbounce2:
Most of my saws are just for fun, or "pre-361" - the 361 could really do it all........
Forgetting me and my birches, what I define as a limbing saw, is one that is really well suited for limbing spruce and fir, with lots of small diameter limbs.