the wipika and hydro are both solid kites. Persoally I LOVE the Throttle Bar on the Wipika and their bag design. The Cabrinha bag SUCKS BIG TIME and I've told them so. The Cabrinha bar (2002)wasnt anything special.
Both manufacturerers have been very good about warranty issues. I've had one for eachbrand so far. No complaints about that.
I own 2 Hydros and 2 CO2's and both fly fine and are built well. There will probably not be a lot of diffenernce in flying characteristics in the 7 M size. I have flown my seven in 30+ knots and it is rock solid in the air.
Given what I said at the top of this post I would probably go for another HYDRO. (i really hate the cabrinha bags...not that that should be a big reason to choose Wipika...but you should look at the whole picture price...features...convenience.)
Where are you getting your deals on the kites? I am actually in the market for a 5M kite. PLease let me know. Thanks