I'll add that I like the XA as a second film body for travel. I'm the original owner of an XA I bought in the early 80s, and it's still going strong. I picked a second one up several years ago as insurance. On vacation travel, I shoot Portra in it and put bw in a Leica. It's great to be able to slip the XA in a pocket when going out to dinner.
The lens is more than good enough. Yes, it vignettes wide open but that's part of its character. stopped down to 5.6 or 8 it's very sharp, with nicely balanced contrast. Maybe not as sharp as a Rollei 35, but with better ergonomics. It's a great little camera.