Gabe -- The Gara's from Cressi are good fins, though you might be more comfortable with the Gara 3000 versus the 2000 which is pretty stiff..perhaps too stiff for less experienced freedivers not going deep. Most beginner freedivers are not at all comfortable with the stiffness of the 2000, and thus gravitate toward the 3000.
You should also check out some freedive fins from other makers, as the Cressi Garas are an integrated fin (e.g. not modular in design). This means that you can never change the blades. Most other freedive fin vendors offer fins that have separate foot-pockets and fin blades, which are fastened together with 1-2 screws and a couple of clips on the side rails. Some other fins I'd suggest you evaluate would be: -- Maker (model):
- Picasso (Black Team)
- Omer (Millinnium)
- Sporasub (H.Dessault)
- Beuchat (Mundial Elite)
- Seac Sub (Genesis)
The Imersion fin.... This is made by Esclapez, a very small French company. I have yet to meet a freediver who uses these fins, or anyone in the freediving community who has written a strong (positive) review of them in the last 2 years. One issue for me (when I was looking at fin from this maker some time ago) was the fact that te Imersion and its cousins, the Esclapez Green and Esclapez Black, all have a two-part foot pocket -- in other words, the pocket itself seems to not be integrated with the rails that attach to the fin blade. I couldn't see these fins as being ideal for freediving, nor did I expect their pockets to be rigid enough. In fact, Esclapez offers the same "Imersion" fin with an open-heel pocket that slips into the same "socket", to attach to the fin blade and side rails. So it seems to be a compromise design, attempting to apeal to both scuba divers and freedivers. Such a fin isn't likely to be great for either market, IMO. If you really lean toward this company's products, I'd suggest the Esclapez Black as the best of their offerings. The Imersion fin is a lightweight by comparison.
Bottom line, with all of the other choices listed above, (and the Cressi Gara's) to pick from, you have a lot of good fins to consider. These (other than the Cressi's) are all modular in design, although some of these makers (e.g. Seac Sub, and Beuchat) do not currently offer the components separately...only together as a complete fin. Omer, Picasso and Sporasub are known for having very good foot pockets....many competitive freedivers use one of these three excellent pockets as a base, and fit them with different fin blades, such as carbon-fiber blades from C4 (Falcons), Picasso, or Omer carbon blades. or similar.
Lastly, be sure to select the fin size with some space to accommodate the water sock (bootie) you will be wearing with the fin. Unlike snorkelers, we freedivers (almost all of us anyway) don't wear our fins on bare feet. A major reason for this (besides exposure protection) is that GOOD freedive fins have very stiff pockets, which help transmit energy efficiently from leg/foot to the fin blade. These stiff pockets would be rather uncomfortable if worn on bare feet. So, be sure to mention your shoe size and the bootie type (e.g. 3mm) you plan to wear with a given fin, and perhaps the seller you order from will help you select the right size of fin, taking into consideration how each vendor's pocket is sized (e.g. some run a little bit more narrow, such as Cressi, whereas others are more wide for the same "size").
Hope this is helpful.