Most people don't go onto a board like this to say "our room was clean." But if you look at the occasional poll about room problems, you'll see that on average the
DVC housekeeping is better than most hotel housekeeping, and that the resort desks come to fix most problems that are discovered within 30 minutes. Our family has stayed at expensive non-DVC resorts where that level of service was a promise not kept.
As for trading, yes, you can do some and enjoy it. It's not worth the points to trade out to West Overshoe Springs. If you want to do a lot of that sort of trading you are, as other posters have suggested, better off buying a cheap timeshare for that purpose. (Be prepared, however, for the fact that the cheap timeshare--especially if bought new--will drop 2/3 of its resale value during the first 15 minutes after you buy it while DVC has historically gone up in value.) There's a poster on this board named Dean who is well-informed on other trading alternatives who can give you great advice.
That said, it's certainly possible to use your points to travel to Hawaii or the Caribbean or the Alps and get good accomodations. It takes flexibility and planning ahead and it doesn't squeeze the very best value out of your points, but compared to first-class hotel rooms it's not a bad deal either. For many families the occasional trade out is part of their points use pattern. Here on the DIS board, the subject attracts diverse opinions. But the universal theme is that you should buy into DVC primarily for use at the Disney properties, and consider Member Getaways or Concierge Collection to be the side dish rather than the entree.