Terraforming Mars is a long game – 5 players can take 3–4 hours – but very enjoyable for serious modern boardgamers.
The publisher printed a bigger run of this than they had ever done, ran out, reprinted double, ran out again, printed double that, ran out again, and are now on their 4th or 5th print run.
The Venus Next expansion adds even more opportunity for “engine building” (cards that piggy back off each others actions), so be prepared for games a little longer than the base game but well worthwhile. We're up to at least 50 plays and still playing strong. The new corporations add new strategies too.