First, the lifepath character generation system, which enables one to create
a character with a colourful background history based on his career(s).
Second, the world building system, which enables one to create a science
fiction background, from the sector of space down to the society of a pla-
net, without any need for a calculator.
Third, the animal generation system, which makes it possible to create any
number of animals of various types, based on the ecology they are a part
of.
Fourth ... starships ...
Basically, Mongoose Traveller does what Classic Traveller did, but it does it
with more detail and less contradictions and omissions. This makes it an ex-
cellent core rulebook for a science fiction RPG, and since it is a generic sy-
stem, one can use it for almost every possible kind of science fiction setting.
I consider it a very good science fiction supplement for BRP, at least until
there is a BRP SF one, because it contains all the basic rules systems requi-
red for science fiction, and they can easily be adapted for use with BRP.
At least that is my opinion ...