See the video links in my signature for a full breakdown of the 24/7.
major differences between Pro and OSS are
ambi decocker / Safety
metal guide rod
extra inch of barrel
the OSS does NOT have the key lock (TSS) that the Pro has though. The pro doesn't have a decocker though either.
i was really sort of sold on the OSS and it does seem superior to the Pro model but i'm going to keep my pro until the 800 series comes out. It has an exposed hammer which i really would like. It's due out next year. See: http://www.taurususa.com/whatsnew/pistols.cfm18.5 lb. recoil spring that cycles the slide faster, a heavy Match Grade 5¼' barrel and a stainless steel guide rod that adds just the right amount of front end weight for improved recoil control and rapid fire accuracy.
If you're not wanting to wait for the 800 series I would pick up the OSS unless you're concerned about size for Concealed Carry, then the Pro might be a better deal.