Both are nice in there own right, I would give the upper hand to HS but I wouldn't say it's like a Mercedes to a Geo. As far as reputation HS has been around for a very very long time. Bullfrog has been around as well, but has really changed and come out of the woodwork the last 2 or 3 years. It's not the same spa it was 4 years ago.
With the question in the other thread, everybody out sources parts one way or another, some more than others but every brand does it, so don't let that sway you one way or another.
Again pick what fits you and your budget best. And a great long standing dealer goes along ways. That being said we have a local ex cal-spa ex Coast and current D1 dealer that is a POS and I honestly do not know how he is still in business with the way he treats his customers. Any spa can have problems, our tech works on just as many Hot Spring spas as he does Jacuzzi and Sundance along with many others and I am sure it goes the other way with HS dealers.