Whichever you choose (you can't go wrong with any unless like me you are really foot heavy.) I would recommend springs.
They are the most comfortable fin you will ever wear I suspect, and they are extremely efficient.
You will hear that split fins silt the bottom. It is not the fin that silts, but rather the kick. Split fins doing the same flutter kick as a paddle fin silt less.
Paddle fins are just better for alternate kicks such as a modified frog kick, which keeps the feet away from the bottom.
I have made at least 2 thousand dives in open heel fins and I find spring straps to be the most uncomfortable strap I have ever tried. The line of contact is just one thin line so the force per square inch is significantly greater than with any stock strap; plus they are more negatively buoyant than stock straps it would seem.
They are the most comfortable fin YOU have ever worn, but nobody has the same shape foot or same comfort zones as anybody else.
If you are doing the same flutter with splits that you are doing with paddles, you are doing the wrong flutter with one &/or the other. The proper flutter for a split is not the proper flutter for a paddle.
It may be "kicking" that silts, finning with fins is a much better solution. I think it is very likely, from my watching thousands of tourist divers each year for almost a decade, that for the typically untrained diver, the split fin just might stir up more sand/silt than a paddle.
Trim / body position along with proper finning is what keeps a diver from silting. When I fin my long blade free dive fins (Gara2000's) in any style (flutter, scissor, frog, modified frog, even dolphin) my trim dictates how far from the bottom the turbulence is, so any finning style can be done with the fins at any distance from the bottom.