I just took at look at their site:
http://www.heartlandrvs.com
Interesting...they seem to be targetting Montana and Cambridge. In fact, the 3400RL floorplan (same designation for both Montana and Heartland) is almost exactly the same. Their other floorplans do have differences though. The Landmark has almost all of the same features as the Cambridge, even including the flat storage area and the reduced belly clearance that the Cambridge has.
The Bighorn includes standard the "Universal docking center" which is similar to the Cambridge exterior hookups and controls. But, they use Al-Ko axles.
The other big thing to note is that they are targeting short bed pickup trucks with their specialized front cap.
I do like the fact that Heartland has some diagrams for their A/V stuff:
http://www.heartlandrvs.com/LMtech_diag.html
I'd like to look at one to see the fit and finish up close, but I think I'd still stick with the Montana.
Fred