Been thinking of a mouse gun as a BUG to compliment some of my S+W revolvers...
I'm leaning towards a S+W Model 351 or Model 317 over some of the smaller autos like Kel-tec, Ruger LCP, Beretta Tomcat for many reasons.
Compliments my existing holsters
7/8 round capacity
revolver reliability
revolver simplicity (important when I consider my wife)
weight
ergonomics...
Oh yeah... I like .22's and it will compliment my collection
Only the Beretta and Walther PPK/S have the ergonomics I like, but the weight and QC issues scare me off.