I've had DirecTV for about five years and it has been a much better experience than what I had with our local cable provider (not Comcast.) I've not had any problems with antenna alignment but then our dish is mounted to a brick wall. My one suggestion would be to make sure the installer choses a stable spot for dish installation. Installers are generally subcontractors (not DirecTV employees) and they can be a bit on the lazy side if you let them.

Note that antenna alignment for the HD channels is much more demanding than for standard broadcast. I considered installing my own antenna when we upgraded to HD last year but went through the installation instructions first. The built in signal strength meter in the receiver is not adequate for proper HD alignment; you need a separate, special meter. Have a pro do it.

That said, I've NEVER had a dish go out of alignment.

As for equipment, I've had no problems with the equipment they've provided. I currently have on HD DVR, one Tivo DVR (standard definition) and one standard def receiver.