If you need to go on a long trip, and you simply cannot take your dog, do not board him/her. In my opinion, that would be cruel. Do not leave the dog at home by themselves while having someone come over once a day to feed them. This can cause way too much emotional damage. The best thing you can do is leave him/her with someone you can completely trust. If you do not know someone like that, then you need to find someone like that.
I cannot help it. I feel that it is cruel to board a pet, but I am not stupid. There are sometimes where boarding your pet is the best alternative. Besides, I am sure that there are places that do a great job with your pet.