Auto Tune has been out longer and there are more saws with it out there, and no manufacturer is 100% trouble free. M-Tronic came out later, and is still just coming out on some saws (like the 362 I am getting), but there seem to be very few problems with it. This is confirmed by people like Mastermind, who likely sees more saws in a month than I will in a lifetime.
If you are talking pro saws, the 50cc Husky has less weight, the 60cc s are very close (I don't think you will feel the difference), and the 70 cc saws it may go to Stihls advantage. My dealer highly recommended the Pro Husky saws (he sells both), but also told me he sells Stihl 3 - 1 to Husky because the non pro Stihls are better (this is what he told me, I have not done any research on non Pro saws). I'm not sure where you got your prices, but at the place I went to they were priced about the same (550 XP compared to a 261 C-M or a 562 XP compared to a 362 CM (in fact the latter two were the exact same price).
The bottom line is if you get either a M-Tonic or Auto Tune saw that has no issues you will likely love it. So go check out the saws yourself and see what you like and make sure you have a dealer that will stand behind the product 100%.
One piece of advice I will give you, get a pro level saw if you can, you will not regret it. They will have better power to weight and be more durable than the other stuff. The size saw you want will depend on your size, your strength, and the size wood you plan to cut. Many people have a large saw (70cc) for felling and bucking and a small saw for limbing and topping. The 60cc 562 XP and 362 CM are often considered good "do anything" saws, and the modern day electronics help them to cut like a larger size saw. I am 6' 1" and 185 and consider myself to be in good physical condition. I have used 70 cc saws for everything for years and prefer a 20" bar, but as I am now in my 60s I want a lighter saw. Limbing with a 70 cc saw may look impressive, but it can get you tired.
Also, if you do not have a lot of experience, don't start with a monster saw, this stuff can get dangerous. That said, most people start small and then wish they had a bigger saw than the other way around. I started with much smaller saws, a Homelite Super 2 with a 14" bar, then a Homelite 330 with a 20" bar (only 1.75 HP). My Stihl 044 (similar to the MS 440 and MS 441) was a tremendous improvement, but it is not a beginner saw.
Hope this helps you, best of luck, and most importantly always be safe.
MustangMike
