I've never had Haas come out for service, but every time I call HFO Chicago for guidance or information they are very helpful and usually point me in the right direction. Sometimes it's very difficult to get through to them, but I suppose they are just busy.
I have to say I like buying parts from them too. So easy compared to any other machine builder. No minimum, reasonable shipping, no credit application or any of that crap. They just send you the parts and send you a Net 15 invoice. Simple. Maybe it's different for large orders, but for orders up to $3000 I've had no issues.
I've had good support over the phone from Mazak, but their purchasing process is retarded. I got stuck at a customer's shop once because Mazak would not ship parts out the same day due to their credit app review process. Also, the last place I worked refused to buy a Mazak because of the lack of support in our area. All of the experienced service people spend all of their time in the big places like Cat and John Deere. Everyone else gets hind tit.