I don’t exactly want to carry this one. It’s a little big for that imo. Also never shot a handgun with an optic on it.
By the way, welcome to forum and HI!!
...and SA's XDM's a very nice choice for starting out too!
Possibly try a few optics out of other peoples 1st? Are many of either type optics.
Way to generally begin search?
Start with what exact model of XDM you have and go from there? It is important! - Know your model!
On either optics, Laser sight or optic sight, look for fitment, where's it going to go or is it going to fit? Are there any modifications needed?
Functions are many besides the obvious, for example: on/off, always on, auto on, shake and wake, auto dimming, self adjust dimming, constant strobe and strobe can vary and be adjustable too. Are other functions as well? Like dual purpose lights and laser.....? Think one saw even had a built in back scratcher.....Am kidding!
You, for yourself, need to think and plan on what you're intentions are for best results? Ask yourself what for, why? Will whatever work for me? - Target shooting? Home defense or whatever?
Not trying to be hard nosed by any means because there's many choices, pro's/con's to some. Brand loyalties? Some is purely cosmetic, some is fitment, some is how functional for you yourself personally. Good luck on your search!