I know this is a cliche, and is said about pretty much every remake of movies, books, music, etc. However, if you've ever seen the original Spacecraft 2000-2100 AD, there's really no question that it's true in this case.
There's not a whole lot of new material in this book- just a few extra ships (in fact, more seem to have been removed than added) and an updated history section. They also incremented the time period by a century and tried to tie it in with modern events to make it a plausible future. Additionally, the artwork has been redone with computer graphics, and most of the line drawing schematics and diagrams have been removed. This is likely a result of the smaller page layout and shorter general length of this book.
First, regarding the change in the history. I don't think anyone really cares how plausible it is, so I'm rather puzzled why the authors thought it was necessary. Also notably lacking are some of the more interesting discussions, e.g. the unknown objects/ghost ships in the original.
The main reason for picking up this title, however, is the artwork. The pictures are essentially remakes of the original- most have only minor cosmetic changes. There's a few new pictures, but they are generally small and look a bit rushed. This is where the book really suffers- the original artwork was painted and had gorgeous detail and a distinct style. The new CGI stuff, with the probable exception of lighting, is simply not as good. It's not even up to the quality of what you'd see in common sci-fi shows, and this isn't a motion picture. Coupled with the fact that the pages are smaller, it's definitely a downgrade.
The descriptive text is shortened as well, and yes there are typos. I'm not overly bothered by this, but the lack of added material is a bit perplexing. The specifications are unchanged as far as I can tell, but the diagrams that graced the old book are gone. While some of those were a bit confusing, I think they added to the overall feel of the universe. One plus on the text aspect: they make it pretty clear which text block goes with which illustration. In the original, it did require a bit of guesswork at times.
I'd advise potential readers to get the original, but chances are that if you want this book you already have the original. As such, it's advisable you just stick with that. It's simply a superior publication, and I'm quite disappointed that the remake is of such mediocre quality.