also, the starship design rules received a total overhaul, with a switch form the basic letter drive system of 1st ed to a power point system hull percentages for drive size. they were also removed form the core rulebook and moved into a new 2nd ed high guard book (and designed to use the same design system for smallcraft, spacecraft, capital ships and stations, without the odd "boundry issues" that 1st ed sometimes had.
personally, I prefer the 2nd ed ship design rules. I'm not sure in what why they are "less detailed", but I;m sure ShawnDriscoll can elaborate for me.
however, outside of the ship system and a few other tweaks, the rules are mostly the same, and a lot of stuff can be imported directly or only with a minimal of modification. flavour stuff is obviously
its also got a lot of pretty new artwork, as well.