Do not sweat reception issues. The Installer will have a tool that finds the best reception. My house is in the sub tropics, I know rain. Does not matter what the source, OTA, D* or E*, if you are going to get a REALLY HEAVY downpour, you loose signal right before the rain. While it is raining the signal usual comes back. It does not happen very often and when it does, it is a good time to hit the head, get a refill, pop some popcorn, or shut your windows. Besides, you are getting a DVR. If this is your first DVR, you will find it is so easy to record events you will watch almost everything prerecorded. If you know it rained while recording a show you can delete it and record it at a later date. The only thing that gets infected with occassional black outs are one time only events, such as sporting events. I can not remember the last time I watched a sporting event real time at home. Give hockey, basket ball, and football games at least an hour of prerecord time before viewing. When people ask you about "have you seen _____ commercial?" You say "no."
The rare black outs are easily overcome once you have experienced the difference in picture/sound quality. After a day with satellite, you will never be able to watch cable without cringing.