I'd also take into consideration of just how long you plan to keep that RV. With routine maintenance and upkeep, I doubt you would ever spend $4K in repairs over, saw, 10 years. Therefore, if you plan to keep it 10 years or less, not worth it. And, as others mentioned, there are probably catches along the way, like they pay for parts but not labor, labor cost is capped at $X dollars/hr, etc.
2016 Keystone Outback 328RL
2019 Chevy 3500HD DRW
1 Slobbering English Bulldog for ballast