Here are some of, what I think, are the key changes.
Organization: 2nd Edition moves ship design from the Core Rulebook to High Guard (which isn't out yet). It also seems to have fewer items and equipment in it (but more than enough to get started) and has moved it to the Central Supply Catalog (available now as PDF, soon in print). They have also vastly improved the presentation of everything with new artwork and layouts. For instance, the Equipment section looks like a mail-order catalog. It's pretty cool.
Chargen: I think chargen is a bit smoother and has been tweaked nicely. They have beefed up the pre-career education section, added a Prisoner career, and tweaked things a bit. My group likes it and we had a blast rolling up characters. Skills have been tweaked as well with fewer skills that are generally better defined.
Combat: The biggest change here is that there is now a mechanic for mixed-mode combat. That is people shooting at a vehicle or ship and vice versa. There have been plenty of little tweaks to make things go smoother as well, but it will feel very familiar to 1st edition players.
The boon/bane thing has already been explained, and I think it is a really good mechanic and makes it much easier to accommodate for some of the more crazy things players try to do.
The thing is that, as of this moment, I couldn't give anyone who is currently using 1st Edition a compelling reason to move to 2nd Edition other than the fact that all new products will be for the new version. I think part of the decision is based on how much you have invested in the extended 1st edition materials such as the extended career books, etc.
