The RASA has a set of correcting lenses inside the OTA, they are advertised as producing a "Flat" field and to be honest, the few images I have seen from one seem pretty impressive.
This is under two hours of one minute subs! I would not say that the stars are perfect in the corners but it looks more like sensor tilt than field curvature.
https://www.astrobin.com/full/399238/0/
If I had some cash to splash I would be pretty tempted by the idea. I have seen an image of the same area with the RASA 8" and an OSC camera and it was pretty flash looking, to me anyway. But I would not go there without a focus motor!