Actually, according to the specs of both companies the 353 weighs in at 11.0 lbs. with 3.3 horsepower. The revs. are 13,000.
The 5100 weighs in at 11.2 lbs. with 3.8 horsepower. The revs on the 5100 are at 14,500.
I've never ran a 353, but according to specs, I respectfully say this statement just doesn't add up.
I've ran a lot of saws. Not as many as some on this site, but the 5100 has become just about our favorite saw. I thought it would be too small, but the more I lean on it, it just seems to beg for more. The saw just flat out screams. My uncle has been in the tree business for 35 years and is a HUGE Stihl fan. He likes Jonesereds too. He just recently ran my 5100. Now, everytime we come to a job, he says, "Get me the Dolmar." I saw him again today and he said his next saw will be a Dolmar 5100. He say he likes it a LOT better than his ms280 and ms290.
Time will tell if it is dependable as the 260, but I'll tell you this: the design on the 5100 is practically perfect. The feel, the balance (with an 18" bar) is just perfect. It's easy to get to the necessary parts and it's designed to let the chips and dust just slide off on the outside. And under the clutch cover, it is the easiest saw to clean that I've ever seen. I just wish it had a compression release.
Just two weeks ago we ran side-by-side a fairly new broke-in 260 pro and a 5100. It was embarrassing. It wasn't even close. Torque? No comparison, the 5100 was by FAR torquier. I felt kinda sorry for the new owner of the 260 pro. But he had a Stihl dealer close by and they are a tried and true saw.
My son and I have been big Stihl fans and we regrettably had to admit that Dolmar has really out done the competition with their 5100 and 7900 models. These saws just flat out have GUTS and the Power Bands to match..
FYI: Saws I've ran and/or owned. Stihl 200t (2) - ms 260 pro - ms 280 - ms 290 - ms 361 - ms 460 (2) - ms 066 - ms 660 - Husky 575xp - 338 xpt California Edition - Dolmar 5100 - 7900
For your work load, I'd say my choice would be the 5100. It's the KING of the 50 cc class, IMO. I try to really be unbiased when it comes to saws and I really like the Huskies I've ran as well. (I hate the darn switch on the 338 though.)
BTW, a GOOD dealer will let you try the saw out RUNNING. A saw in your hand running feels different than just holding it in the store. Try them both. The 'feel' of a saw in my hands is extremely important to me. The 5100 is just right. It's just a better saw. (I haven't even mentioned the vibration levels.)
All this was comparing the saws as the same price. As a matter of fact, if the prices were flipped, I'd still buy the 5100. For example: if a 260pro cost 390.00 (which is what I paid for the 5100) and a 5100 cost 480.00 (which is what a 260 pro goes for) I'd take the Dolmar every day of the week and twice on Sunday. Please don't tell anyone, I don't want the prices to go up.
Take this advice for what you paid for it, I hope it helps.
+1.
I was going to type out a long well thought out reply but Yasha has already said everything that needs to be said.
I have 2 5100`s and they are my favorite saws to use. I am a proffesional arborist. I use big saws and small saws everyday. I like Stihl and Dolmar but the 5100 is my favorite saw to operate.