I'm not Jake, but I thought I'd throw in my 2c anyway.
I would go for the built in gen simply because it's very nice to sit inside the RV and crank it up to run the micro, AC, and/or whatever else you need it for. The alternative is to go outside to crank it up in whatever kind of weather is out there. This is especially true if you are on the road overnighting in rest areas, truck stops, Walmarts, etc. Built in is much more convenient, and either way you will have to carry it along so the weight will be there.
The first TC we had from '78 to '93 did not have a gen. and we often found ourselves in situations where AC, micro, etc. would be nice, but nothing to power it with. That became a priority when looking for the next TC that we had from '93 until '16. We're looking for another one now and it will have a built in gen.
Our campers have all been 11.5 feet long, and so will the next one. IMHO, it's the best way to get more space and amenities.
I would feel the same way about a MH, and most of them, including ours, do. We've never had a TT or 5er, but I've camped while hunting with several TT owners who used portable gens. They seemed to be satisfied with them and could just carry them in their truck bed when traveling. That wouldn't be possible with a TC.
1994 26' Fleetwood Flair, 454 TBI.
1994 30' Monaco Dynasty, 5.9 230 HP Cummins, MD 3060, 1992 Geo Tracker.