My thoughts on the Split:
It feels kind of awkward and uncomfortable until you get up into the anterior fornex (not that I actually know anatomy... but you have to push it pretty far back. Think of the Jollie, and expect the Split to be thrust all the way back into the snail's tail.
Once you get past the narrowing of the Jollie (is it bad that I think of my vagina as an inverse-Jollie?), then it feels really, really
good. I had expected it to feel good against my PS-spot and G-spot, the g-spot where I usually stimulate it with the Smooth S shape or VIP or something, and the PS-spot where I like an organic cock driven down right at the entrance, or the Fun Factory Wave flipped upside-down... but it's uncomfortable where I had expected to like it.
It's very very amazing when you put it deeper, though. Like Bianca said, it's hard to thrust (because it winds up back in the uncomfortable zone if you go more than a few inches with your thrusting), but it feels really good slapped and rocked (like a Jollie). I'm sure power queens would enjoy a Hitachi at the base too.
So there's my two cents! Shallow, ouch; Deep, omgoshgood.