I was wondering what difference there is in performance between the Tier 5 ships that can be earned through promotion to Rear Admiral (like the Assualt Cruiser), those that can be bought at the C-Store at the same rank (like the Vulcan D'Kyr) and those that require a Vice Admiral character to buy at the C-Store (like the Long Rang Science Vessel Retrofit). The latter two tiers of ships cost the same number of points, so I wanted to know what difference there was in performance in general. Thanks a lot.

T5 ships in the C-Store generally have a Console or special ability that the free ships don't. The Galaxy Refit has Saucer Separation, the Excelsior has Transwarp locations, the Dreadnought has a Lance, etc. In general they're not really much better then the free ships. I have 7 VAs and only 2 use C-Store ships.

They also have slightly different BOFF configurations - though they still have the same number of BOFF abilities. For example, the Excelsior has a LTC Tac BOFF while other Cruisers only have at LT. That makes it a little more offensive but a little less defensive. You gain something and lose something.

The C-Store ships can be fun but you're not really gaining that much extra, IMO.

Just to add to this;

The normal non-c-store T5 ships have a standard configuration for the Boffs and consoles. Boffs are Commander + Lt Commander for the primary type, Lt for both of the remaining two types and one Ensign for the 'secondary' type. eg: Assault Cruisers are Tactical oriented Cruisers (Engineering) so they have the extra Ensign boff station. Star Cruisers trade the Tactical orientation for a Science one.

Consoles follow the same pattern. 4 consoles for the primary, 3 consoles for the secondary and 2 consoles for the remaining.

The c-store ships can/usually mix this up, by giving the Lt. Commander station to another boff type, or shoving the ensign to the primary etc... They're simply alternatives and aren't necessarily more powerful than the standard non-c-store ships but can complement a speciality if you are looking for one. That's on top of the special consoles or innate ship abilities.

Performance wise, there really isn't too much to be gained. It's more designing a decent Boff layout and knowing how to use abilities when the situation calls for it than anything else.