I've had my Voyager Signature Edition since March of 2008. I really enjoy it and have used it live and on recordings. However, I have an aversion to taking it to gigs since it is quite large and bulky and I'm always worried something will happen to it.
With that in mind, I decided to buy both an ATC-X and SE-1X from SE, to determine which one would be a viable replacement on the road.
As someone who has both products, I can honestly say that the SE-1X is much better programmed (the presets blow away the Voyager ones, that's for sure). And it also has very powerful bass. And as another poster pointed out, it is ridiculously funky and great for R&B.
The ATC-X, which I didn't think I would like, has been the biggest surprise at all. It can easily create the most monstrous basses you've ever heard (even more than the SE-1X) and can also be wildly frantic and ugly or ethereal and beautiful. The Voyager by contrast is rather "safe" sounding. The four different filters of the ATC-X are very cool.
That said, I'm still keeping my Voyager because I love the interface and it is quite satisfying to use it in "non-standard" ways. And on special occasions I still do bring it to the gig and it looks very sexy on stage!

I think the original poster was right to upgrade his SE-1 and that would be the advice I'd give to anyone else in a similar situation.