about 2 years ago I saw how many elite swimmers had adopted the Arena Powerfin pro and got a pair...
They are plenty stiff/powerful and a bit heavy which helps you work on the up kick. I use them quite a bit, even on some distance freestyle sets. The idea is to keep the kick nice and compact and they do a good job with that.
The Arena and DMC are pretty similar but I dont think the DMC are as heavy.
Canadian Record Holder 35-39M & 40-44M - 200 m Butterfly (LCM)