I'm not a professional tree worker, but I have done a few dismantles/removals. Seems I always get requests for jobs that require rigging everything out of the tree. Anyways, I've owned a Stihl MS250 for many trouble-free years, and my first in-tree saw was the MS192. Does it perform like the 200 or 201? That really doesn't matter to me because I'm not out to make a profit (do work for friends & neighbors). I find the MS192 is quite sufficient for my needs, including blocking down a spar. I first spied the MS150 a few months back in Culpeper, VA and I could not get it out of my head. So I bought one in May from a dealer in Virginia Beach for $439.
Again, I'm no pro, but I am 55 years old. The light weight of the MS150 is perfect in my book for those occasional days when I'm in the tree for 4 or 5 hours straight.