Well, I've had an Inspiron 1564 for close to a year now, & it hasn't given me any trouble yet (except for the battery dying out). So I'd say the build quality is pretty much satisfactory. (Hope I haven't spoken too soon).
However, what I would suggest is trying to look into reviews (by the common junta on forums & such, not professional reviewers) for the specific model you are going to buy. That'll probably be a better indicator. HTH. Good luck.