In a nutshell, I think Omnia could be a big seller here in the States while Innov8 is much more suited to our friends in Europe and elsewhere around the globe. Why? Omnia's a slim full touchscreen candybar phone in the style of Instinct, but it features high-end multimedia features and Sammy's TouchWiz UI, with all of its finger-friendly widgets and customization options. That stuff's hot in the states right now (just ask Apple), and Omnia promises to offer a potent combiation of of WinMo 6.1's power and ubiquity with a user-friendly UI skin the likes of which HTC fans have been enjoying for awhile now. Plus, the new-fangled optical mouse system actually looked pretty interesting, as it offers some handy options like scrolling mode (as opposed to full cursor control).Innov8, on the other hand, is a somewhat chunky slider phone powered by Symbian OS. While Innov8's 8MP camera has already drawn a lot of interest from cameraphone enthusiasts Stateside, Symbian devices just haven't really caught on here outside of a hardcore group of Nokia enthusiasts who use unlocked devices primarily on AT&T. Cingular/AT&T have carried a few Nokia E- and N-Series Symbian phones in the past, but they didn't exactly do brisk sales. So many US business users are tied to Windows Mobile that there's honestly not much room left for a "utilitarian" smartphone platform to gain traction here. And let's be honest - S60 can do a ton, but it's not exactly flashy.
So I'd look for Omnia to show up in some form on a US carrier. Hopefully it'll be soon, and hopefully whatever carrier(s) pick it up will more or less leave TouchWiz alone save for a little branding and maybe a few widgets. More importantly, the truer the US versions stay to Omnia's impressive spec sheet - 7.2 Mbps HSDPA, WiFi, 5MP Camera w/flash and video recording, 8/16GB internal storage - the better.
But I wouldn't hold out for a US carrier version of Innov8 anytime soon. I could be wrong, but if you're looking for a Samsung cameraphone with 8MP of imaging power, I'd say your best bet is to pick up an unlocked Innov8 through an importer just as soon as they become available. Either that or hope that Samsung takes that camera tech and plants it in a handset better suited for our American stylings. Sooner or later, you know that'll happen.