Go with which ever one feels better in your hand.
I prefer the SIG over the S&W.
The SIG P-6 (P225) is a German police trade in gun. Due to the influx of all the German polce trade ins, the value of used SIG P-225s has dropped. Used ones use to sell in the $500 range. The SIG P225 (P6) is a great gun, very accurate and reliable.
The S&W Model 908 is one of the last metal framed non-1911 semi-auto pistols that S&W made. The Model 908 was the econo-line version of the Model 3900 series. The S&W 3rd generation pistols have good reliability and decent accuracy. I use to own two S&W 3rd generation pistols (Model 3914 & Model 4014), but got rid of them. Did not care for the trigger pull, slide mounted safety and magazine disconnect.
“If someone has a gun and is trying to kill you, it would be reasonable to shoot back with your own gun.” - Dalai Lama (Seattle Times, 05-15-2001).