The GUI improvements are a huge step forward. MTA is certainly more unified. And judging by the screenshots, it feels very polished and every side of it (client/server/server listing) has been seriously taken into account.
But the most important thing to me is stability, it has been a major headache to everybody and hopefully (as I've read) most of those nasty regular crashes were sorted out, thanks to all the bug reports.
Excellent work, I can't wait to download and try it out!