I spent an inordinate amount of time and angst trying to decide between the XI and XA myself. I was reassured by many members I would be very happy with either. I went with the XA once I decided to take the plunge and switch out a couple resistors inside my preamp's moving coil section to adjust to the XA's very low .2mv output (a result of its non-magnetic air coil design). I'm still not yet set up (my arm has just been returned from re-wiring). I could not have gone with the XA without doing this, and I'm still nervous about it.
Bottom line: the XI's .5mv output means you will have ZERO gain problems. I'm sure you'll be delighted. Let's compare notes once we're up and running.