I bought a cheap no-name sharpener on eBay 5 years ago and have to say it was a good buy. It's been well used by myself and 2 sons over that time. Between us we have 5 chainsaws used for pruning, farmwork, fencing and mostly firewood cutting. Usually we'd do about 5 hand sharpens and then the electric. Conservatively, I'd say we've used the electric near on 200 times over the 5 years. I've only had to replace the cutting wheel twice but due for another change. Four spare wheels came with it so I'm not sure if they'll be easily got when needed. The hinge joint is starting to get a little wobbly so I'll probably end up replacing the unit in the near future anyway. I initially bought the cheap one mainly because I couldn't at the time justify spending near on $500 for an Oregon sharpener as recommended by my neighbour who is a professional tree cutter. Oregon's have come down in price since to around $350 but for the value I've had out of the cheapie I see no reason to buy the brand name model.
I use a proper sharpening jig with the guides etc. (made by Stihl) and I find it works very well. I have used an electric one before and wouldn't use it again for several reasons. Firstly, because it is so short, it is hard to keep it straight therefore ruining the set. Secondly, it has the potential to heat up the steel too much therefore destroying the temper. Thirdly, it does not set the depth. The Stihl sharpener I use was $60 and you can replace the files on it for $4. Great system; - it sharpens and sets the depth guide at the same time. Only problem is that if you have more than one saw, you have to buy 2 as each size chain has a different sharpener, not just file size. I reckon you should give it a go mark as going to the Stihl shop and paying $15 each time you need your saw sharpened doesn't really add up financially; -and it doesn't really fit the philosophy of self-sufficiency that well either. You just have to take your time and maybe watch a few youtube vids on the subject.
I agree with bearded1 regarding the hand held electric sharpener but that's not the type that I'm using nor is it like the Ozito that Director is looking at. I also use the Stihl 2in1 guide in the field which sharpens the rake and sets the depth in one action. Doesn't matter how careful you are the angles get messed up and that's where the bench type sharpener resets the angle consistently. It's the type the shops use.
I've never watched a youtube video on chain sharpening just followed the instructions that came with my saw. My manually sharpening isn't too bad but I have to say it probably wouldn't hurt for me to see a few instructional videos.
If I got a sharpening device the electric bench type appeals to me the most. I love gadgets