I can not really comment on the specific model 5th wheel that you listed but can tell you that we have had our Flagstafff 528RKS for 3 years now and it has been very trouble-free. It tows well and seems to be sturdy built. Ours is a 2019 that we purchased new 3 seasons ago.
2017 F-350, CREW, SRW, 6.2, 4.30, 4X4
2014 Coachmen 310BHDS