SV is the best. STI is close (in fact, nearly identical functionally), but the SV is more of a full custom job, whereas the STI is more of a limited production type gun. On the other hand, SV is extremely expensive and has long lead times to get your gun made for you. A STI Eagle 5.0 is about $1,500, while a similar SV Infinity is more like $2,500+.
Not only is Para not anywhere near as good as a STI or a SV, which is an unfair comparison given the price difference, it is also not as good as the 1911s made by other companies at the same price point, which is a fair comparison. And I for one don't suggest buying a crappier gun just because it holds more rounds in the magazine. There really is no such thing as a good, affordable, high-capacity 1911 right now.