I own two XDM 10mm's. The 3.8" and the 5.25, as well as various 9mm's in the 4" range, So, I won't be getting a 4.5" XDM 10mm. However, my experience with Springfield's 10mm's has been excellent. Barring issues on how you plan to use this pistol and holster/carry comfort particular to your situation; I couldn't be happier with the reliability and shootability of the XDM 10's and unreservedly can recommend them to anyone who asks. I even located inexpensive IWB/OWB holsters for the 3.8" that are very comfortable and work great for CC. I haven't tried the Smith M&P 10mm, and the SIG was too pricey for me, so I can't tell you how it feels by comparison, but, when it came time to make a decision and plunk my money down, I chose the XDM and haven't regretted it.