Haven't yet used it, but it looks well built. If it does the job it's described to do, it will help out immensely.

This thing really works! I had my doubts and bought the added warranty with it, but upon first use of a sharpened chain, I was convinced I had made a great purchase.

I cut a lot of wood. Use this to file down rakers and sharpen both a large and small saw. No issues. Easy to use.

After reading the reviews, I decided on this purchase. I'm a DIY type of person with a above average mechanical background. Recent Ice storms have put a strain on all my chains. I have a 18" Poulan wild thing, and a 10" electric pole chain saw. The first thing out of the box I noticed the depth gauge nut did not fit tightly in its recess nor was it a full sized nut. After finding a proper thread pitch and size nut, it fit much tighter in the recess. I put a dab of silicon on it to help it insert and stay in place. Mounting holes are not shouldered at the bottom so whatever you use will have to catch the top of the mounting hole. I decided on a pair of 5/16" X 2" carriage bolts and mounted it to a piece of 1/2" particle board that fit into a drawer on my workbench. I did use a pair of 5/16" fender washers to distribute the pressure of the nuts below the mount.
Once mounted, I plugged the unit in and turned it on. I must say, I was not impressed with the initial sound. It sounded weak and slow. So I mounted a chain into the sharpener, and as a previous reviewer stated, look for the two identical teeth (cutters on the same side) as a starting point. that way you know you've made it around. Next, adjust the chain link lock so that it grips the drive link tightly. You can adjust the knob easily by pulling out and setting it back to tighten down more securely. Set the turntable to the desired degree setting, adjust the link stop, adjust the depth gauge and you are ready to go. At this point you're on your way to sharp chains. I did every other cutter, then switched to the other direction so you'll go around the chain twice. I did on purpose go into sharpened links twice and must say that you could tell you'd been there already. Very little cutting would occur.
My concerns about the motor were unwarranted. It did just fine for the conditions. It's a sharpener not a bench grinder. As a kicker, I set the turntable to 0 degrees and used a bungee cord to hold the grinding wheel down. On the pole saw chain, since it had been sharped for the second time, I decided to touch up the depth gauge paw. I would pull the chain under the grind wheel. The depth gauge adjustment let me knock off just a smidgen so that the top plate was back in specification. This might not be for everyone, but had to try it for myself. Overall, for myself, I think this will work fine for my needs.
If I were to find cons, lack of a simple LED work-light and location of the on-off switch would be better located on the handle by your thumb. Simple quality control like the using real nuts instead of whatever they were using.
Pros, The price of this unit and the amount of times we have ice storms that warrant the overuse of my chainsaw make it a useful item to keep in my arsenal. The four chains that I sharpened have already paid for all but $1.99 of the cost of the sharpener.

UPDATE: I've run the sharpened blades on the both chainsaws now and am very impressed with the chips and shavings that they are creating. See last photo.

I reviewed many comments here and finally purchased this machine. I am pleased with my purchase.

The first comment that gave me pause was that the sharpener needs to be attached to something permanently. No issue for me. I set it up easily on a workbench and gave it a permanent home.

The second comment was that the instructions are sparse. Well, I have yet to read the instructions, yet was able to set up the unit and sharpen my first chain successfully in about 15 minutes. There is a stop for the chain links, a stop for the grinding wheel depth, a setting for the cutting angle and setting to grip the chain securely.

So, in order...
1. I set the appropriate cutting angle
2. I set the chain gripper to secure the chain while sharpening.
3. I placed the chain in the gripper.
4. I placed the first link in position for cutting, setting both the chain link stop and the grinding wheel depth stop.
5. I secured the chain
6. I sharpened the first link. Released the chain gripper.
7. Moved the chain to the next link with a similar angle using the preset stop. Set the chain gripper. Sharpened the link. Repeated until all similarly facing links were sharpened.
8. Placed the wheel to the cutting angle appropriate to the remaining links.
9. Repeated steps 5, 6, 7

I sharpened the chain in a fraction of the time it took to write this.

One comment from a user was that each link needed to be set for sharpening individually. That is not the case. Set the stop for one link and the setting is correct for all. The user said that it took him 40 minutes to sharpen the chain. It took me less than 5 minutes to sharpen the chain. EASY.

Other comments were about the cheap quality. I agree that all of the stops are easy to break. But using care, should not be a problem. Additionally, once they are set, they don't need to be touched again unless you are sharpening chains from different saws.

And if the plastic stops bother you, I would urge you to visit the nearest hardware store and replace with steel.

My appraisal is that this is a fine machine for the average homeowner. If it lasts for four sharpenings, you will be ahead. But I expect that with care, the machine will last much longer than that.