Since you want on the market today I will leave out all those that went under.
Northwood. Only mass produced with in house frame left with very thick aluminum side wall construction and stout roof truss's.
RV Factory maker of Luxe. A Lippert frame but strengthened somewhat. When Augusta owned I thought the best fit and finish I have seen since the old high end maker days.
Riverstone Legacy. Lippert frame but it has an all steel deck. Only Forest River product that has it. Thick walls and fit and finish seem to be very good.
DRV. Never been a big fan but lots of features. Look nice. Lippert frame and is boxed.
Spacecraft. A custom manufacturer that will build anything. Take in a drawing on a napkin. They will build. In house everything.
New Horizon. Custom unit also and seems to be the only 5 star rated. Uses polystyrene in walls like Teton and Nuwa use to.
Best seems to be subjective to everyone but these units to me have something that seperates themselves from the pack.