I've rented the XD in 9,40 and 45 on several occasions, my very first handgun purchase was an XDM45, and I currently own an XDM9 and XDM45 compact, so I'm fairly versed in the platform. in my opinion the XDMs are a huge step up from the XDs but since the XDM45 uses the same mags as the XD45 which gives them the same ammo capacity the differences in that particular chambering are a bit more negligible. the XD45 does have issues with semi-waddcutter ammo but unless you are a home loader that casts your own bullets, your odds of ever using it are pretty slim. the XDM fixed the SWC feeding issues so that is the major advantage that they hold. other than that I see no real flaws with the XD design. the XDM has longer sight radius, less blocky design and better grip textures so I still tend to favor the M factor when it comes to 45ACP. with all that said, I would still rather own an XD45 over an FNP45, glock 21, M&P45, beretta PX4, USP45, or sig...uh.. whatever their 45 models are, and if ruger ever releases an SR45, I would still take the XD45 over it.
people are free to knock them all they want, at the end of the day I know that they are just better for my purposes than any other gun.
EDIT: I just read that you already ordered one...good for you, looking forward to the range review.