Tiffin was probably one of the last of the FRED producers. Production of the Allegro Bay ended n 2010 when the Allegro Red came out. Built the Bay on the Freightliner MC chassis with a 6.7 ISB mated to an Allison 2350. Shocks/leaf springs for a suspension along with hydraulic brakes. Other than the power train not much different in general than the Ford.
The chassis did have a higher weight capacity and better fuel economy but it wasn't enough to entice potential buys past the increased cost. A 2010 Allegro 38TGB listed price was around $170,000. Same floor plan on a Ford chassis was $150,000. Economic factors at the time didn't help. The Red listed at around $180,000 at the time and was a full up DP chassis so might as well get the real thing. Many builders followed suit with the lower cost, call it "entry level", DP and the rest is history.