Problems with pre-lit, artificial Christmas trees?

This year for Christmas, I want to get my mom a new Christmas tree. We have a fake one that is looking rather worse for wear. While she longs for a real tree, the convenience and cleanliness of a fake one is too appealing.

Do any Flutherites have experience with artificial trees, specifically ones that come with lights already on them? Are burnt-out bulbs annoying or easy to deal with? What trees have you found that are most convenient?