My impressions after the first few hours of gameplay (with the new Loa):
The good:
-turn times an interface transitions seem to have improved (mind though that i didn0t have to much trouble with them earlier either...)
-the loa are quite interestin to play. THey are completely different than the old races in almost every aspect (you NEED to read the EOF manual or you won't know what is going on with them)
-the loa are the biggest expansionists (after 50 turns i have 20+ colonies)
-the ability of the loa to change any fleet into any other ship composition is huge bonus (e.g.:my survey fleet returned, lets position a gate with them and after that use it to colonise the newly surveyed system)
-new traits for admirals (some of them bring rather interesting advantages, now especailly for combat fleets there are many interesting choises)
-you now have the option to issue orders the 'old way' (you select a fleet and its order and than its target, but you can still do select target/select mission/select fleet - mind though that not all missions can be ordered that way, but most can (i'm still using the SOTS 2 way because i got used to it, but i tried of the new feature works and it worked

))
The bad:
-there is a minor interface bug with the loas, where ther 'gate capacity' is labled as psy power
-their new drive system could need
a bit more of explanation, especially the inteface to build the gates (but after a few trials what that slider does i figured it out)
-a bug with placing stations as the loa (my workaround was to reposition the construction fleet to the system before giving build order - so i can live with it before it will be fixed)
Other stuff i haven't yet played (much) with, but it sounds awesome:
-new tech treee and new techs in the existing trees for all races

(since i played Loa i haven't yet tried the new tree)
-new sections for existing cruisers, dreads; 2 new leviathan types (one which allows you to move any defensive assets)
-new modules
-new weapons
-new mission to evacuate population
-new randoms and GM (i didn't yet get any of those new ones)