Regarding freedive fins - that is like trying to pick out underwear to give to someone - more times than not, the recommendation is not quite on the mark.
Here are some general guidelines:
IF you want more compliant fins, look at Cressi 3000's - have heard they are great for divers looking for a softer blade fin. IF you have the money, look at the Waterway #1's or #2's (I have the #2's and they are wonderful - a glass composite material made in Eastern Europe) Stiffer fins can be had just about anywhere - Mares, Sporasub, Picasso, Omer all make plastic fins that in my opinion are too stiff for all except the stronger diver. I dove Picasso Black Teams for several years and come to find out they were killing my technique due to the lack of flex in them.
Foot POckets: If you have narrower feet - look at the Cressi's for sure. Very compliant pocket I have heard that is comfortable even bare foooted. IF you wider feet like I do, look at Omer or Picasso (I love my Picasso foot pockets) The cold mold rubber they use is the stiffest I have found to date.
Replaceable blades: Omer and Picasso Make fins that have user replaceable blades. If you go with the Waterway blades, they can be purchased with Omer foot pockets.
Plastic -vs- Glass -vs- Carbonfiber: There is a never ending debate on this one - I've dove with plastic and Glass composite and swear by the glass blades - I'll probably never dive plastic blades again. I know of freedivers who swear by carbon, but I can't justify the price of admission to get a pair.
As far as video goes - I highly recommend it as a tool for improving technique. It's what was used to discover my BT fins were killing my technique when I trained with Aharon Solomons earlier this year and is what I use now when I teach a freedive course.