It wasn't very difficult to fit, more fiddly than anything. The instructions weren't brilliant, being mostly pictures and few words. That suits me fine, though, because it avoids all the poor translations you usually get. I've put a few of these on bikes before, so perhaps I found it easier than a first-timer would, but I think anyone could manage with a little bit of time.
Since I've put it on I've not had to touch it - it has worked flawlessly. Seems like a fairly heavy duty piece of kit, not going to be damaged by any bumps you might have. Feels sturdy enough to go through a bigger accident, should you be prone to that sort of thing. For the hardcore, I'd perhaps recommend something a little bulkier, but then anyone who is into that probably knows what they want anyway.
It's capable of doing everything I require, the usual max/average speed, trip distance stuff. The elapsed time feature is especially useful, though, for me - it records the amount of time that the bike has been moving for, so you can get a far more accurate measure of the time you've actually spent riding.
Very happy with this little thing, debating buying a second for one of our other bikes.