I've been going to them since they split off from the BMW dealership and opened the new shop. Now, I didn't buy my bike there, but have been getting service, and I've always been happy with the service & parts depts. They've been through 3 service managers, which was a concern, but the latest guy, James, seems like a good guy.
As for prices, I try to spread around my business to keep shops and vendors I like in business. If I pay a few bucks more for stuff at Marin that's OK, because I know when my bike is fried (like it was last weekend) they'll be there to do a quick fix on Saturday. If you build up a relationship with a dealer it'll pay back dividends; if you just go from place to place trying to get the cheapest deal that relationship won't develop and you're on your own. That may work for you, but I prefer to work with people I know and trust.