I guess I am in the mixed opinion group...... Depends on the split fin. On a trip to Bora this past November I brought my good ol'e 20 year old Apollo Bio splits and was just fine with them until one of the molded "hubs" where the straps connect sheared off when I went to don my fins for the 2nd dive of the day. They had some cheap Aqualung rental blades and I used those and immediately noticed a big difference on the positive side. More propulsion for the same effort and more importantly....more overall "horsepower" if I really wanted or needed it. Basically, the Apollo splits worked just fine in easy conditions.....but if I really wanted or needed to get up and go......I found that I could actually "outkick" my splits to a point where they just would not give me any more. Not so with the blades. I tossed the splits and now my go to fins for warm water are full foot Mares Quatro Plus Avanti's with spring straps.
But....... for drysuit diving up here in the PAC NW........ I also tried the Avanti's and didn't really like-em. I then tried some XL Scubapro Split Jets and love-em. It might be because the foot pockets on the XL Jets are HUGE and my big ass feet and drysuit boots fit way up into the pocket.
Anyway...for me...it's the Avanti's for warm water and the SP Split Jets for cold water drysuit diving...
But....... for drysuit diving up here in the PAC NW........ I also tried the Avanti's and didn't really like-em. I then tried some XL Scubapro Split Jets and love-em. It might be because the foot pockets on the XL Jets are HUGE and my big ass feet and drysuit boots fit way up into the pocket.
Anyway...for me...it's the Avanti's for warm water and the SP Split Jets for cold water drysuit diving...