One of Starfleet's oldest (more than a century old) and best proven designs. Has oldest technology, but is extremely reliable, and a very efficient design. Multi-mission vessel, suited for deep space, far away from chain of command, where a ship needs a balance of science, speed, endurance, and tactical capabilities. Science labs. No holodecks. Very maneuverable compared with larger, more recent ships. Relatively inexpensive in comparison with the huge Galaxy and Sovereign ships. Less expensive to operate than later-era ships. Relatively spartan crew quarters, at least as compared with more recent ships. Old-style duotronic computer banks.
Speculation: The fact that this ship has distinctly separate modules (saucer, engineering, nacelles) might suggest that this makes for more efficient warp drive compared with ships (like Defiant and Voyager) whose geometries are more compact. (The newer ships, of course, have more powerful -- and expensive -- engines to compensate.)
ABOUT THE STARFLEET SPACEFRAME PACKAGE:
Every approved Starfleet spaceframe assembly includes a standard set of structural and operational systems. For example: self-destruct and warp-core ejection mechanisms, lifeboat complement, Jeffries tube network, Bussard ramscoops, reaction control system, docking ports, and fluid handling systems. These and all other systems not specifically available for selection in this design program are automatically included in every starship design.