Here is a link to some info on the 2010 range: Liquid Force kite 2010
The Envy uses the same USB 2 bridle as the Havoc, the Hifi Comp has no bridle, just the 5th line.
Due to no bridle the Hifi has a very direct feel and a good bar pressure, the Envy is very direct for a bridled kite, I like C kites due to the direct feel but actually really liked flying this kite.
The Hifi Comp is the best kitelooping kite, its loops fast and powerfully. It pulls smoothly and constantly all the way through the loop and it keeps pullling and climbing fast all the way back up.
The Hifi Comp is faster and quicker response, but the Envy is a quick kite aswell, it has a thin leading edge so is fast through the sky but also quick in the turns, much faster than I thought it would be. The 10m is fast enough to loop.
The Envy would be best in the waves as it will drift better and is mega stable
Upwind they are both really good due to the thin leading edge making them efficient so can be pushed to the edge of the window.
Envy has very slightly lower bar pressure than the Hifi Comp. Envy pressure and bar feel is really nice though, much more direct than other SLE kites.
The Envy is similar to the rabbit but faster through the air and smoother (and a lot cheaper!). It is less delta shaped as it is 'delta inspired' so it doesnt have the bad qualities of delta kite which has made it much more stable and solid. The RPM is more like the Havoc.
The three struts makes it light (1lb lighter) so no backstall and very responsive but still rock solid