The Twin Jet fins are excellent, and very popular (though you'll find that many folks like to make fun of any split fins). I have a pair and have many buddies who own a pair of them as well and love them--never get a cramp while using them.
The Quattros are one of the staples of diving, and are great for pretty much any style of diving and kicking. Especially so for strong propulsion.
My opinion would be for you to keep and enjoy the TwinJets, and if you get a drysuit buy a set of the Quattros for dry diving (you'll need a larger set of fins to go dry anyway, and will want more power to push the bigger suit through the water).
You will get much advice and many opinions on the topic of fins, but ultimately your comfort and satisfaction is what really matters!
theskull