USPSA Open division? SVI or STI as a base. For some reason I see more
STI in Open, SVI in Limited. You want to buy "off the rack" or have a gun built to your specifications? Where are you? There are good gunsmiths
all over---I REALLY like to deal with one I can get face-to-face with.
IMHO. Don't worry about the name of the gun parts maker. Its the gunsmith that counts for an open rig. I think it just depends on yoiur area as far as which brand is more popular. My limited rig was built by Freedom Gunworks. It has parts from all the big names in it. They build some wicked open blasters there too.
Both sti and sv are great company's. I've had great dealings with both. Sti's edge over sv is sti is a bigger company and can make parts faster.