Hi,
I've owned all three and still have two of them; I sold the µ-II to raise some cash towards a CZ Planar for the M9.
The XA is nice and there are still people around who can repair them, you can leave the flash at home and so on but it is a RF and they are a bit fragile to carry in the pocket. My first one, when they were new, got an expensive knock and put me off them for everyday use.
There's little to chose between the µ-I and µ-II apart from the size and spot metering. In theory the lens is faster on the II and the spot metering is useful but in practice I've never seen any difference at the print or slide stage of using them.
Both the XA and µ-II can be used against the light with the XA's +1½ EV switch and the µ-II spot metering doing the trick but the µ-I does fill-in flash and that works as well. That's assuming you mainly do the usual wife/GF with sun lighting up her hair shot...
There's lots of other AF small P&S's with some useful controls/overrides like the Leica minis and their family, the Pentax, Konica and Minoltas also come to mind. And there's the bigger Canon and Nikon and so on P&S's with RF's and AF built in. (But some have battery problems, meaning designed for mercury batteries; f'instance the excellent Konica C35 RF.)
EDIT; a minor but important point is that all of them will be elderly second-hand camers and so it's best not to pay too much and do a thorough film test. My µ-I got five stars in my tests and so did the Konica A$, C35 AF and Leica mini 3; the list could be longer but I have only graded cameras I currently have...
If you are patient you can usually pick them all up dirt cheap as small film cameras are often undervalued off of auction sites.
Regards, David