Bob... I find it a bit difficult to work with because I got too used to the width you get from the 35mm. However, it's truly great to see all you can get in a single shot!
My lens had a bit of separation (sent today for repair) in the rear element. Otherwise, the focusing throw is reasonably wide, the lens is very sharp and... what can I say? Probably the only problem we'll have is that the barrel does protrude too much into the VF, especially with the hood on.
As for problems that can occur in all RF lenses... mine has never flared or given internal reflections. Still need to work on it to gauge the bokeh quality, but at least in regards to sharpness... no complains!
See below one of the few shots I've scanned... Probably not the best, but it'll give you an idea. Or so I hope! 🙂