I've stayed there twice. I think the main issue is how far out of town it is.I have just (~3 weeks ago) returned from another Barossa trip.
We stayed at the Novotel Barossa Valley Resort which was quite adequate. I'd certainly say that it is a step up from motel style accommodation. Being winter, the main facility which got some use was the restaurant.
Breakfast is a little steep at $35, and $5 coffee tax, although they did have a deal at check in which brings the breakfast price down to $20. Next trip I would contemplate going to a local cafe.
The al a carte dinner service was good. BYO wine available at $20 a bottle, otherwise they have a reasonable list with normal restaurant pricing.
My biggest complaint is probably the acoustics of the restaurant on a busy (packed) Friday evening. There were a couple of large groups booked in and the buzz of the room was just a little too loud for my liking, no doubt exacerbated by the acoustics.