Merits of 1st In vs Space 4e?

[lentulus]

I am looking for a good written (PDF format) set of rules for Hard SF system & world creation. I have played traveller in the distant past, but the systems I see most often recommended are both from SJG: Gurps Traveller First In and Gurps Space. I am not running an SF RPG per se, but looking for good generic tools to put together a hard sf universe.

The obvious difference is 1st In is slightly cheaper, but Space looks like it may have more useful secondary material. However, at the core, what differentiates the two world creation system?

Is Gurps Traveller still in the hexadecimal world of traveller as I knew it, or can 1st in be used without the overhead of other books?

Does either of the systems use metric, or are they both US common units?

What other points can I use to guide my choice? I will be buying one or the other in a week, so guidance would be appreciated.

[SCAR]

Both are available as PDFs from e23, which means there are Previews available:

GURPS Classic: Traveller: First In - 6 page preview available
GURPS Space (4e) - 12 page preview availables

[lentulus]

Originally Posted by SCAR

Both are available as PDFs from e23, which means there are Previews available:

Tables of contents and indexes are helpful, and got me this far, but no real substitute for experience with the rules. Anyone built worlds with both? Either? Have a favorite?

[sjard]

As I understand it, Space 4e uses an expanded version of the rules from First In (both by the same author). I think the Space version has been made slightly more generic and slightly less specific to Traveller.

Hope that helps.

[SCAR]

You could start with this thread, and it's author Brett who it would appear has done substantial work with creating worlds using the Space 4e rules as a starting point.

[Fnugus]

I think GURPS: Space is a great book. I don't have any experience of Traveller: First In, but the Traveller: Interstellar Wars for 4th Ed. GURPS is also a very nice resource. I like their system for building spaceships better than the one from Space/SpaceShips.