To the OP, you really can't go wrong with any of the pro 50cc saws. I personally am lucky enough to own a Husqvarna 550xp, 346xpne, and a Stihl 261, among others. I'm also a firewood cutter/firewood scavenger(we heat exclusively with wood, although we do have a heat pump for back-up,but it doesn't hardly ever get run during the winter), I even started selling a little firewood this year. I get most of my wood from Craigslist, 3 family farms, and the occasional neighbor, including blowdowns and standing timber. I'm not a professional by any means, and I'm definitely not "big time", but all my saws are used at various times throughout the year. My saws are tools, I don't have any "shelf queens" or "collector" saws(even though I like to keep my saws well maintained and looking good). With that being said, here are my opionions on these 3 saws(all 3 are bone stock and have been owned by me since new).
The 346xp has great acceleration, smooth a/v, handles excellent, and starts easy. It's also my first Husky, after being a huge Stihl fan. I haven't had any issues at all and in no way is it cheaply made or any less durable or dependable than the other two. It really bothers me when people make claims that it's flimsy or not well built, but those same people haven't produced any fact based, evidence that something was broken off the saw or that it experienced "pre-mature failure" vs. any other saw in it's peer group. My 346xp does fall over when you set it down, but I think that is the dumbest argument ever used, to try and discount the quality of a saw, it really is a "clutching at straws" type of argument. I also don't believe that the 346xp "cures cancer", or that any other saw ever made now or in the future will achieve that feat. I have used this saw to limb, buck, and even felled some hickory with it, and it did a great job. The 346xp is just a great light-weight, good running saw that does what it is designed to do very well. I have never been dissappointed by my 346xp.
The Stihl 261 is another fine 50cc saw. It always starts easy, runs strong, and has more torque than my 346xp. It handles well enough, just not as nimble as the 346xp or 550xp. Some people complain about the weight of the 261, to me it is heavier than the 346xp and 550xp, but a few ounces is not a big deal to me. I wouldn't call the 261 a fat pig, by any means; the reason I say the 261 doesn't handle as good as the other 2, is that I believe the 261 is a bulkier design and is not as ergonomic, compact, and slim as the Huskies(I also do not buy into the "sideways" balance thing). The 261 also has the best air filtration between the 3 saws, not to say the other 2 or bad, but I believe the Stihl is just better in this department. The Stihl also has great a/v and is also comfortable to use. You can't go wrong with a 261, it is a very solid saw.
The 550xp is the "new kid on the block". IMHO, the 550xp is phenomenal, it seems to combine the best elements of both the 261 and the 346xp. It is the lightest of the 3 saws, but has the acceleration and throttle response of the 346xp and the torque of the the 261. I think it handles better than either saw and is the smoothest of the 3. I haven't felled with it yet, but I have bucked, limbed, and even noodled some 30" pin oak with it this summer, it is an impressive saw to say the least. The 550xp has all the bells and whistles auto-tune, rev-boost, and captive bar nuts(just like the 261). The only thing I don't like about the 550xp is that it is in the shop right now for warm/hot restart issues. I try to be fair and honest of my views and opinions, the 550xp is the only saw out of the 3 that I've had any trouble out of and the only 1 that I've had in the shop for any reason. I knew(before I bought the saw) that with any new technology there might be some "growing pains". I also strongly believe that my 550xp is the exception and not the rule. I don't think one "bad apple" spoils the whole bunch. I have zero "buyer's remorse", and IMHO the 550xp is the best of the 3, but what works for me may not work for someone else. If you are looking at purchasing a 50cc saw, the 550xp is definitely worth a second look.
I have also heard alot of great stuff about the Dolmar 5100 series, but I don't have any experience with Dolmar saws yet, so I won't comment on a saw that I haven't used.
Just so you know, my opinions are not influenced by Sawtroll, Indiansprings, or the internet/AS in general(no offense to these 2 aforementioned members). These are my real world impressions of 3 great saws from the point of view of a "firewood hack". To the OP, I hope this helps.