I have both a SW40GVE and a Walther P99AS, very similar to the SW-99.
I only bought the Sigma because it would be a good, cheap "truck gun" and the ergos fit my hand perfectly.
Before I shot the Sigma, the Walther was my favorite semi-auto.
A few weeks ago, I was at the range with both guns. The Walther is my sometimes carry gun, but I was still trying to find out if the "cheap" gun was still reliable with hollow points (it has been so reliable, I was sure it would eventually fail me).
Long story short, I hit the target easily and quickly with the "cheap" Sigma. The Walther, with its superior trigger pull, took a lot more effort to get good groups
After shooting several hundred rounds from both guns, I was forced to admit my beloved Walther was inferior to the cheap truck gun (sigh).
I also do not find the Sigma to be hard to conceal in an IWB holster; however, I'm 6'1", 240 lbs.
The Sigma is also now my bedside gun.
You usually get what you pay for. But once in a while, you get much more than you pay for.