Yes have flown both but not same size the rpm is one of my favorites lighter bar pressure, faster turning and it sits in the window in a different spot .They are different kites altogether, remember the features of the RPM are not better, just features and to some riders they could even be a negative the swithchy is a good kite .And Remember the RPM is one of my Favorite kites.(so im byass)
have fun
GEORGE 
I've flown both in the 12m Sizes.
Apparently the 12 isn't the greatest example of the RPM, the 8 and 10 are supposed to be the sweet sizes.
The RPM needs to be ridden hard and fast... If you put it in the water it will take a little longer to relaunch, but if you know what your doing it will reward good riding. Great pop, boost and unhooked performance, as well as fantastic down the line wave riding...
The Switchblade is a do everything kite - we use them in the school, our team riders push them hard and they take it all in their stride. Relaunch is great, boost is great, unhooked is good for a bow kite.
If you want a kite that you can freeride on, unhook a little bit, send it and do some nice boosts - then the switchblade is the kite for you... It also has a few knots more low end power.
If you want to unhook lots, do kiteloops, ride waves and just generally want to push yourself - the RPM is a winner... It will need 1-2 knots more wind to get you powered though...
The Switchblade is much more like the Slingshot Octane... Those 2 kites are hard to pick the performance differences.
Cabrinha have gone for the freeride side of the market (for the last few years) - a Beginners kite (Convert), wave kite (Nomad), freeride/all round kite (Switchblade) and a race kite (Crossbow)
Slingshot have gone down the performance route (For ever really) - All round/Freeride kite (Octane), Performance kite + wave kite (RPM), and the crazy kick your ass Fuel...
