Heartland is the name of the manufacturer; Sundance is one of their models (along with Landmark, Bighorn, and several others). They are a fairly new brand, about 3 years or so. Website here:
Heartland RV - Fifth Wheels, Toy Haulers, & Travel Trailers If I recall the story correctly, the founders formerly worked at one of the larger, mainstream manufacturers and formed their own company to address what they saw as shortcomings in the market for a mid-priced entry. The Sundance is their mid-price; the Landmark and the Bighorn are the expen$ive (and heavier) models.
I looked at the Sundance model when I was shopping for an RV last year, and found them fairly well-equipped for their price point. I liked some of their floor plans, and gave them pretty serious consideration. IIRC, the 2900RK had its fridge in the very rear, and the slideout prevented access to it unless extended. That was a big design flaw from my perspective, as it would prevent me from making a quick snack on the road (e. g. , at a rest area or truck stop) without taking time to extend the slide. One of the other things that made me decide against them was that the closest dealer to me at that time (about 4 hours' drive) was shall we say, less than helpful.
I eventually ended up buying a 5th wheel made by Crossroads (website here:
CrossRoads RV, Fifth Wheels, Travel Trailers, Destination Trailers, Park Models, Toy Haulers, Recreational Vehicles ) Their "Cruiser" models are comparable in features and price with Heartland's Sundance line, as mid-entry level 5th wheels. Despite some minor issues, I am continually impressed by the number of "standard" features on the Cruiser, which is also what drew me (and I suspect you too) to the Sundance line.
I can also tell you that Crossroads has been very responsive in addressing warranty issues with me. However, since I ended up not buying the Sundance, I cannot offer any first-hand experience with Heartland's long-term reliability or customer service.
Sorry that I wasn't able to fully answer your questions, but hope that helps some.