I have three gas saws of various sizes and decided to try this out. Always been a Milwaukee fan for battery tools and I like this saw. It struggled a bit with ironwood stumps but got the job done. For general cutting it's great.

Lots of power

I want to preface all my Milwaukee M18 reviews with a disclaimer that I do not and have never worked for Milwaukee, nor have I ever accepted anything form them. I Just started switching my 15-20 years of electric tools collecting over to, almost all, Milwaukee 18V. I studied Quality in Manufacturing and have experience in many different construction fields of work that have required lots of different tooling. These tools, so far, for the price, have excelled in the many aspects of quality, upon first use. I have had a couple of defective's sent (different tools, and from eBay, but was refunded immediately), but every single one that has worked out-of-the-box has been great. I am reviewing several Milwaukee items, as I am switching over from the rare 20V Craftsman Professional Red/Black/Silver series (one of the only real 20V sets) that, I believe, was unbeatable when introduced, for it's price point, but was only manufactured for a few years. See below for this tool's review. I'd also like to add to my reviews that every lawn tool has improved my quality of life with outside upkeep much since I have back pain that is easily irritated by 2 strokes and other combustion engines. All of the lawn tools run very smoothly but I also only use the 12.0 Ah battery, as you get the best bang for your buck.

Out of the box:
PROS:
-The blade was already tensioned decently but nuts could've been tighter.
-Put oil in it and ran it plain for a bit to lube it up. It uses the perfect amount of oil, in my opinion, to keep the blade well oiled and the parts moist enough to keep easily cleaned.
-Upon my third battery use, I got the bar stuck in a decent Russian Olive. Thought I was for sure bending the bar or losing the chain. Neither happened, they're still great. The tree popped off and the saw came out with the chain needing a little tightening. I even destroyed the tree a little more before tightening the chain in retaliation Muahahaha.
-Also, on third use, I gave it 9-kinds on the ground on its side for quite some time, trying to cut through heavy roots, stump, and dirt of a Russian olive(I believe, I'm no botanarian). This thing was tough trying to cut through. I had it most of the way chopped up on it before the saw quit. I thought I'd finally drained the battery. Put another in and nope, wouldn't do anything. I'd clogged it with dirt and everything (this was after cutting up a ton of other dead stuff) and the motor was overloading so the overload protection was working perfect. It would barely click over if you'd wait and pull the trigger every 5 seconds or so. I could tell it was having a hard time with all the dirt/debris in it. After about 10 attempts, it freed everything up and started running like a beast again. I called it a night then because I was already worn out and my chain was getting that way too. It had gone through a lot and was on it's 3rd battery.
-Very easy cleanup. I took it to the garage, disassembled it (easily with the included tool), cleaned with mineral spirits in my tank (making sure not to blow liquid directly at it, blew it all out real good with compressed air, oiled it all, put it back together with my new blade (I'll sharpen the 1st in the meantime), and it's like mint condition again, aside from a couple tiny spots of paint on the bar that have came off where the hardening was done.
-Oh, the little hidden tool for tightening is excellent and stored nicely. I've wondered why this hasn't been a thing for years.

CONS:
-WTF is up with the trigger area, Milwaukee? It has a hole for a foot like you're starting a combustion engine pull-start but isn't necessary. If anything, it makes for a nice huge storage spot for the wonderful little wrench. The battery bay needs moved behind the hand grip/pointing under it, giving the tool a better balance point. I bought this tool to replace (hopefully) my Stihl 2-stroke 14" topping saw in the picture that can often be used 1 handed. So far, it's doing great with it's ease-of-use and power with the 12.0 Ah batteries. but is a little tough with 1 hand
-Need more than 1 battery if you're going to be working a lot. I feel as a homeowner of about 4 acres, 1 wooded, I need about 2-3 12.0 Ah batteries for the Chainsaw, Weedeater, Hedge Trimmer, and Blower when needed. I don't usually need to use them all in the same day but there's no way you'd need over 3 with how much work you could do plus if you had to have some on fast charge. You can wear yourself a little with 1 session of a 12.0 Ah battery on about any tool, although 2 batteries often guarantees you'll get done what you need.
-The teeth by the handle need to be a little longer, probably 1/8" even. It does grab a lot of the time but if there is something small in the way, the teeth have a hard time getting to the material.

Conclusion: I think if this saw was made more like my Stihl topping saw, with the battery weight distribution in the back, handle grips closer, and a lit...

I got this during one of Milwaukee's deals so I wasn't as out of pocket as I would have been if I'd paid retail. I was skeptical about how well it would actually function being an electric, especially with a $400 retail price tag. I had played with one for a couple minutes but just on small stuff, nothing that would give any electric I have used a problem.
I can now say I believe this is a valid Milwaukee product. As much for the new 18V 12A batteries as for the saw itself.
A group of us went out with 2 of them and used one to cut down an 80+ foot tree (I'm not sure the type of tree, it was dead and some kind of pine). I used my saw and cut a little under half of it up into rounds between 8 and 10 inches. Limbing and cutting it into rounds did not take the battery down to 50% (I also used it on some other misc cuts).
My comparisons are other $80-150 electric corded saws, I have not used any other cordless chainsaws. It performed better than any of them.

What I would be confident recommending it for:
Landscaping companies (especially if they are using Milwaukee 18v blowers and hedgers) (the 12A battery would be a nice addition)
Arbor companies looking for a finishing/small job saw
Framers (buy a couple extra batteries)
Home owners (if they actually need a chainsaw)
4x4 excursions or back country frequent travel of any form (clearing roads and trails)
Ranch/Farm with acreage with moderate or less tree work
Arbor companies looking for a finishing/small job saw

I would not recommend this for anyone actually performing logging tasks (maybe a limber if they want something small). This like any electric chainsaw will never match a good quality gas chainsaw (I have used 20" to 30+" bar saws).

To the point made below about the chain popping off regularly. All electric saws need to be tightened on a fairly regular basis (the two nuts holding the bar on come loose on electrics), they just require more maintenance in this regard. I set it, ran it a few cuts, set it again and ran it for the rest of the day with no problems. I checked it when we were done and it was still ok. I will be checking it again the next time I take it out to make sure it doesn't need to be tightened and tightening the two nuts if they need it.

I can also say I don't know how good the bar is. I have not pinched it and do not know anyone that has. It held up fine for what we were doing but really for a bar it wasn't much of a test. If I do have to replace it I will be putting an Oregon bar on it like I've done with the other saws I've owned/used. The chain seemed to do fine but again I haven't really used it that much to have to worry about it going dull.

Very useful tool