I have purchased several items from Harbor Freight and for the most part they are not to bad. Just be careful what you buy. For example, I bought a hammer drill from them. After using it for drilling about a half dozen holes, 3/8" bit, in cement, the chuck is just about gone. It is very hard to tighten a drill bit in it.
I think the best thing is that you have to remember, if it is something you will be using often, it probadly won't last long. Their drills and such appear to be for lite usage only, like once a year and will not hold up to constant use.
That doesn't mean I don't go there, I just watch what I buy. Durability depends a lot on price but they do have lots of very useful items at really good prices..