my 2 cents:
I'd suggest using a CT laser on a pocket gun to groove in your steadiness of your hand and breath control at the range for a few minutes, perhaps using snap caps, then put that HG down and use the three dot sights of your XD-M but using the 'skill transfer' of the steadiness learned with the red dot CT to improve your aim. Sounds odd, but for me I shoot tighter groups on paper targets by grooving in a 'steady hand' with the pocket gun (Kel-Tec?), then briskly, but safely moving to your XD-M. Thought I haven't fired it much at the range on my K-T, it's helped me quite a lot in acquiring a steadier aim and a more instinctive aim just using it with snap caps at home.
The LG-448 is the right CT for the XD-M (see link below, with pics), but unless you have specific, ideal conditions it isn't very useful tactically.
OTOH, I would suggest the Viridian or the Laser-Max green laser for the XD-M because you can push button attach and detach, and you can clearly see the green one even in daylight.
What I'm getting at is a CT laser is an ideal training device with snap-caps but not so useful as your EDC. It's also hard to find a good holster right now for the trigger guard type of red laser.