Owned a Pony, have shot the SIGs on several occasions. Not really an apples-to-apples comparison as the Pony is DAO and out of production, while the SIG is SA and can be had in several different flavors. I liked my Pony, but only after sending to Cylinder & Slide for a workover. Even then, it was never 100% reliable. If I were a single-action kinda guy, I'd buy a SIG in a heartbeat, even over one of Colt's new-production Mustangs (which I have also shot).
I owned a 238, had numerous failures, and decided I didn't want to have to depend on it to save my life if I ever had to use it. It was a sweet looking gun but I'd rather have something that shoots consistenly. I carry a p3at now (the opposite end of the spectrum) and it has been great. Build quality of the Sig was top notch though