Yup, the Vaporshark is indeed ~$30 less. I own both (both are DNA 20s 'cause I've had 'em for a while). I have a second XPV on order, but I'm content enough with just one Vaporshark for the time being.
The drawbacks to the VS for me are the 1200 mAh battery (which would not get me through an entire day away from power) and the fact that at roughly 19mm thick, it just doesn't look quite right with a full-sized (22-23mm) topper like a Kayfun on it. In addition, the switches simply don't have the "This is going to last forever" feel that the switches used in the XPV do.
Vaporshark is supposedly working on a big brother to the existing model which will presumably have room enough for an 18650 in it. To do that, they will need to grow the unit 3mm in width, 3mm in depth and 7mm in height. That will make its proportions just right for use with Kayfun (or similar topper). If they keep the price under $200, I think they'll sell a metric ton of them. I'll certainly buy one (because I can, and I like to try new stuff) but I doubt it will replace the XPV as the one mod I'd grab if I had to go someplace all day (or longer) and could only take one.