We just traded our Class A gas motorhome for an Alliance 310RL 5th wheel. So I can not compare to other 5th wheel, e.g the Grand Design other than having seen the one that our neighbor has.
So far, after some 2000 miles traveled and 2 weeks in the camper, I am very happy. There were some startup issues, most annoying the improperly functioning leveler. But this was more an LCI fault and the replacement controller and sensor were were installed by the dealer (Bish's/Cheyenne) while we were waiting. Otherwise, we still need to find out why the zillion USB charge ports are not working and the main TV is not on the Inverter AC circuit. But that is just minor niggles.
Otherwise, it seems to be a well-built trailer with some upscale features and we did not see some of the cheap quality issues we had with the motorhome. Super-large tinted windows, and 3 A/C units to deal with that...No outside, plumbing or shower door leaks, no paper-thin film on the cabinets, a real residential 4-burner stove/oven, large fridge, large shower, king bed, so nothing to complain. It even came with a solar system that is supposed to be optional. Got a good deal and fair trade for the motorhome.
So far, I really can recommend it. But It is no surprise not to see much replies because there are not yet many around. And, before you know it the company may be sold to Thor anyway...