Hi Glenno,
There are a few big kites on the market, and there is no definitive kite that will tick everyone's boxes.
Riding style, board size and model, wind conditions and also body weight make up the cocktail that gives you the best idea to what kite suits a particular rider.
There is no one kite that is perfect for all riders. I sell Core Riot XR LW's and also Ozone Zephyrs. Both are 17m's and both are excellent kites, both are very different, depending on your requirements either may suit you.
Tips for buying a big kite (or any kite for that matter).
1. Find someone who can offer you more than one option
2. Find someone who actually knows what they are talking about
3. Find someone who can back up their options with demo's
4. Demo the kites in the wind strength you want to fly in, on the board you wish to ride on in the style you want to ride in. That way you'll know what works and what is Hype and BS and what is real.

DM