I sell and own one of these... But I have the H3500 for my whole home. It cost more, but works wonders. As far as wear and tear, you have nothing to worry about, the way the systems set up keeps it in check. I'm not too sure on the ERR on the computer part, but the H3500 has a computer connected to it that will tell you all the levels to make sure things are going right, it tells you when its time to add salt to allow the self cleaning of the filter, and even how much gunk it has removed from your water.
With the H3500 you also get the under sink filter, a back up system for just in case something does happen and you need the whole home one fixed. In that package you get them both under the same price... but if you really don't care to have it just say no, I didn't add it to mine... as long as the main one does its job then I have no worries.
The warranty covers every little thing, and w/ the computer set up they can fix any electrical program problems from there office. As long as any wear and tear is from just daily use, they fix it for free, and even replace anything on it if need be. The only way the warranty won't cover it is if you purposely do something to it to break it down.