Swipe blows ass compared to SlideIT. I will note, however, that SlideIT is geared towards elite power users.
I'll try it, but color me skeptical. I don't see much room to improve on what Swype does. You draw over the letters of the word: it types out the word.
They function in the same way, however, Swype's dictionary sucks. It makes up way too many words, the helpful hints that pop up all the time suck. SlideIT learns your words/phrases/etc much quicker and seems to be a lot more intuitive that Swype ever was for me.