I actually do own both of these sets of speakers and went from the Omnis to the Studios in my main system. The Omnis have a sense of openness to them and that's why I still use them as surrounds. Corndog is right, though, while the Omnis are spacious, the Studios are transparent and crank up the level of detail by a lot. the Omnis dig deeper (room dependent, i suppose) but if you already roll off the low end, it suggests spelunking bass is not necessarily your jam.
My desk situation is similar to yours except I use Encores instead of Omnis. I tell you, though, if I had the space and resources to upgrade them to another pair of Studios, I would do so in a heartbeat. They're pretty magical.
