I've seen videos and reviews of these things and they look really good!
Now for the only negative I see with the whole MP vs. WP: The WP unit is completely inside the tank, wire and all. This will put off some heat, not a lot, but it will, more so on a small system. The MP on the other hand has the motor externally so any heating would be minimal as it would have to transfer through the glass or acrylic.
With that being said, I think there is great value to these and it's just a matter of the above and if you want something of that size in your tank. If you have koralias or tunzes currently and looking at going with these, I'm guessing size-wise it's not that much bigger. If you're an votech person, then you'll go with the vortech. In a larger aquarium the heating would be minimal anyways.
Me personally, I like having less equipment in my tank. That's the entire reason I bought a vortech. But if I bought a larger system and could find a creative way of camouflaging the pump, I would probably go with the WP's.