I go here a lot because it's close but I have been to other dealers around the valley. I currently own a HD, so I'm not in the market for one but they do seem to have a large inventory of new and very nice looking used bikes. You have to walk past them to get to the parts department (typically where I go) The sales staff all say "hello" and even when I'm ogling the new bikes and tell them "I'm just looking" they back off and don't seem to stalk you, which is cool.
The guys at the parts counter are really helpful and the ladies at the cashiers station are always very nice.
They seem to have a fairly large inventory of parts. I've asked for some oddball stuff and 90% of the time they have it on hand. The items they don't have on hand and have to order come in within a few days and they always call and let me know when it's in.
When my bike was in warranty I always took it to them. No bad experiences there. They were always in contact with me to update progress and advise me about what was going on. The bike was always in and out in a day.
Now that it's out of warranty I do my own maintenance. I put around 350 miles a week on it so the scheduled checks come up fast. I still go back and talk to the customer service people on occasion and they are happy to offer advice when I need it.
Overall they have friendly staff, large inventory of parts, and good customer service so as long as I'm riding and needing parts, Arrowhead HD is where I'm going to get them.