Is the "M" really that much better than the standard?
Unless you have some pressing need for something the M offers for competition use (don't really know what that would be), or just have to have the replaceable backstraps (I don't), I don't think so.
I own a couple of XD Subcompacts (9 & 40), and checked out the M line when they came out, but so far I'm unimpressed. 'Course, I'm a pragmatist, and my primary use is for SD.
Pretty much forgot what little I knew about 'em when researching 'em as I quickly decided I wasn't interested, but if I remember I told a few folks if you were looking for a HD gun with max capacity and don't worry too much 'bout size, the 9mm ain't a bad choice-I seem to remember the 9mm XDM holds more rounds than the XD?
A couple of things I didn't like 'bout the M line:
Match Grade Barrel-considering how accurate mine are (and they're subcompacts), I can't see the match grade barrel offering any benefit.
Take different magazines than the regular XD line.
Looks (subjective), but I like the regular XD better.
Novak or ? rear sight-for a SD type gun, I prefer the older XD style sights-the flat front of the rear sight blade lends itselft to one-handed operation.
Don't recall if the rear site on the M is adjustable, but for a SD gun I prefer drift adjustable sights.
The XD 45 Compact has been on my want list for way too long!