I put the 10-20 on my camera in the shop and tried some interior, some outside walls, neighboring buildings and city horizons which proved to me for my intended purposes that this lens would be more effort to correct in pp than it was worth. Big vignette and distortion on this guy - maybe not so much his fault as that of such an extreme focal range. Also, it is very difficult to capture meaningful detail at this range with subjects being so pushed away. Its good if you like to capture everything you see before in a single frame, but it doesn't look 'real' anymore. Its an effect lens if you enjoy skewed perspectives of super-wides, but it had four strikes against it before 5 minutes of use for me and I had gone in wanting to like it.
I might investigate the 15mm limited when it comes out hoping a new prime in this range is better corrected, but what became clear was that my best bet for wide shots was deferring to my existing FA31 and stitching if necessary.
Can you go to a shop and try this lens? Might help you know if its for you or if you'll discover it isn't, and no LBA is left lingering