I eagerly looked forward to it, I have it, I've read it... I haven't done anything with it, except make up a pair of practice characters.
It looks pretty good, I've not really read through all of the world descriptions yet. That they all fit into the UPP system is a help, and the many, many planet maps are a big plus.
I like that it merges, rules-wise, with Traveller. I like the emphasis on cyber implants, computer interfaces and DNA-mod packages. I'm looking forward to messing with the space combat, as well as other combat.
I was always more a fan of 2300 as a setting for wargames than as an RPG-- I never really grokked what to do with it, except that my brother and I loved Star Cruiser for a short while. No one else around us wanted to GM, so we drifted away.
Of the groups I play with now, two are heavy on the hack 'n' slash, so I could easily whip up some Kaefer fights. One is more into detailed RPing, so if I come up with a good game concept someday, I'll break it out.