We looked at the 28BHBE when we bought our current camper. The biggest reason that we didn't buy it was heat and AC vents. The bunks in the back don't have any ventilation, especially if you close the blinds. I grew up camping in a bunkhouse without good ventilation... it would get HOT in that bunk in the summer.
We bought the 29QBS that has a (small) bunk room with an AC and heat vent. That has kept my kids cool in the summer and warm in the winter when we camp.
I've not seen a 29DHDB in person, but it looks like a nice floor plan... but the bunk situation looks the same as the 28BHBE.
We have an outdoor kitchen on ours and love it. I thought it was a gimmick at first, and wouldn't have paid extra for it... but now we absolutely LOVE it. We love cooking outside, not getting smells and extra humidity inside. It allows me to cook breakfast and my wife to cook dinner and still socialize with friends and family. The outdoor kitchen allows us to get drinks and fruit during the day without waking the sleeping kids, without letting AC out, without letting bugs in, etc. Its not for everybody, but we were surprised to learn how much we enjoy our outdoor kitchen!