Well CBM seems more popular than the base game. With the base game its essentially a rush to collect as many gem generators as possible (clams being the most popular) and then heading straight for a tartarian factory ASAP.
CBM has been around for ages and has almost become the standard mod for many many games, nearly all use it in some form or another.
All my MP games have been with CBM 1.6 and/or Endgame diversity mod (EDM) and I have to say that compared to the vanilla game they really do add quite a lot, more viable strategies and less micromanagement as well as a fair amount of balancing out all the really ridiculous stuff. A big change is making the gem generators unique. Several nations are rebalanced true but not usually major changes, lots of it seems to be focused on making weaker nations viable choices rather than making any particularly powerful.
CBM 1.7 is not what I would reccomend at this point as it is a major departure from what most people would expect. -no hammers and other weird things.
EDM is really good as well for giving alternatives for tartarians, they're still good but not the only option anymore. Its not a major mod it just adds a few lategame summons to give non astral or death nations a chance to get some SC's. It seems really well balanced to me.
So yeah CBM 1.6 and possibly EDM 1.1 would be mods I would support being used.
CBM 1.6
EDM