These ships are good and can be considered sidesteps or possible upgrade paths to the ships pointed out by the Recommended Progression.
The Cobra V brings extreme agility, and high firepower for a small ship. But it has a smaller distributor and the same small power plant as the Vulture, limiting it somewhat. Odyssey or ARX is required to purchase.
Compared to the Alliance Chieftain this ship trades speed and maneuverability for more healthpool and more hardpoints.
Basic: Coriolis EDSY Cr
Full Engi: Coriolis EDSY Cr 92.6M
All things considered the FAS is a straight downgrade from the Alliance Chieftain, offering worse hardpoint convergence, worse optional internal layout and worse lateral/vertical thrusters. Viewing past these deficiencies it's still an interesting and potentially fun ship to try.
Basic: Coriolis EDSY Cr
Full Engi: Coriolis EDSY Cr 81.4M
This ship combines many strengths (Good shields, speed, boost multiplier, laterals/verticals, hardpoint placement), which makes it extremely effective in PvE, and marks it as the meta in PvP. The reason it is not part of the recommended progression is because the available medium-size weapon choices and the ship's handling are less newbie friendly. This build uses efficient beams, so range control is a must.
The obvious comparison for the Mamba is the FDL, to which it loses on hardpoint placement, maneuverability and optional internals, gaining only speed in return.
Basic: Coriolis EDSY Cr
Full Engi: Coriolis EDSY Cr 136M
For people who don't own Odyssey: the Krait II is very capable, flexible, and beginner friendly, sporting more firepower but being less maneuverable than the Chieftain. For Odyssey owners and more advanced pilots, the Corsair is more powerful but demands better piloting skills, and the Python Mk II is also more powerful but far less flexible.
Internal Layout is very similar to the Krait Mk 2, but it gets a very different flight model, slightly more tankiness by having bigger shield cell banks, and cannot fit a fighter hangar.
Basic: Coriolis EDSY Cr
Full Engi: Coriolis EDSY Cr 194M
A top contender for the best medium combat ship, the Corsair brings higher speed, more firepower, and more defense than the Krait 2, but it doesn't maneuver as well, and its hardpoint placement may require more careful aim with gimbaled weapon, or your fuselage may occlude your shots. Odyssey or ARX required, but no Imperial rank is needed.
Also a worthy contender for the best PvE ship in the game. Compared to the conda it gets even better survivability, but it loses the great hardpoint placement in return. Having two converging huge hardpoints can only partially make up for it.
While this ship comes with a unrivaled combination of tank and speed, the remaining maneuverability specs really leave to be desired. The hardpoints however are also good and the C7 distributor not a very significant issue.