It depends on the work you're doing mate regarding the 241 vs. muffler modded 550XP. I own and run both.
Everybody here seems to be talking "cut times" when we should be talking efficiency - dropping saws into cants is good fun but it doesn't give an indication of fuel economy, filtration, throttle response, how good the spikes are at biting in from different angles etc etc. There are so many variables here that it's a pretty hard call to even comment on what is a better saw. The 550XP is an absolute weapon but I find myself reaching for the 241 more and more. If all I was doing was cutting 12-16" wood all day the 550XP would be perfect. When doing domestic type jobs however with a variety of wood sizes the 241 is a great saw.
With arms outstretched all day limbing the 550/261 will definitely tax the arms more than a 241. Just remember that the average AS member is nowhere near a full time saw operator and "saw fitness" is not something that comes naturally (just like forearm pump in dirt bikes). That little bit of extra weight will certainly be noticable by somebody who doesn't use saws much.
