I presume the quad para foils you are talking about are the Quadrifoils
These are great and a lot easier to fly than the rev. They come in
various sizes 2sqm to 5sqm and the good thing about them is that they
have no spars, so they can't do any damage nor can they break. Here in
the UK they are fast becoming the favourite power kite to tow buggies.
They do generate a lot of pull. The small one will drag the flyer in
moderate to heavy winds and the large ones are really manic. A word of
re-assuarnce however is that they are very controllable so the heavy
pull doesn't get on top you. They are also good for novell stunts, like
launching straight from the bag !! They are slower than flexi's and
not really for precision but very manouverable overwise.
Do yourself a favour and buy one they are great fun !!!