Livefreeordie -
This topic has had some discussion on the forum before, see the thread:
http://www.keystonerv.org/forums/showthread.php?t=4037
The Alpine seems to be positioned between the Big Sky and the Montana with some (IMHO) major differences, specifically the insulation. Admittedly, neither of these three models are DRV Dreamsuites, but they don't carry the hefty price tag or hefty weight either.
As you can see, my DW and I have a 2011 Alpine 3640RL. Overall, we are very happy with it. Sure, it had a couple of "surprises", specifically a kink in the fresh water fill line, at first. But like many on the forum, I'm fairly handy. And like others, I can't leave well enough alone, so I have modified and added to the fiver. You will find my modifications and others' modifications if you look through the pages of postings and threads. However, the above mentioned thread does specifically compare the Alpine to the Montana.
It all boils down to what you (singlely or collectively) want. Floorplan. Price. Compatibiliy with the tow vehicle. Etc. And chances are that you will have a bug or two, but a good attitude will help with dealing with dealers and Keystone and the good folks on this forum can offer excellent thoughts and advice.
Good luck in your quest and Happy Camping!
Ron