Both are good picks, IMO.
I played CT from the '80s till the year after MgT came out - jumped onto MgT as it seemed to have many appealing concepts. I've since gone back to CT - with more house rules courtesy of my MgT experience.
My style is very roleplay focused, though. CT (LBBs 1-3, actually) is better for that, IMO - as there are fewer rules to contend with, and the mechanics are a lot more situational and Referee dependent.
MgT expands chargen, skills and overall number of careers. The events and connection rules are popular for establishing backstory relationships. But, like with the latter LBBs (4 on), I find the number of skills acquired overkill (and munchkin-ish, IMO).
MgT uses a universal task mechanic. Which seems good - in theory. CT has about 2 dozen skills with unique mechanics defined for most. However, in play CT just has a target and maybe a DM or two for each check. Whereas MgT has 100 documented unique skill checks that follow the task mechanic (and several that are exceptional) and require multiple DMs per check to be accounted for, such as skill, difficulty of task, characteristic DM, timing DMs, mutli-tasking penalty DMs, plus task chaining and situational DMs. Which result in one of 6 levels of success (assuming they don't saturate the 2d6).
This is not too hard, per se, (though in forums I find most people forget to account for half of the potential DMs - which could lead to friction in play when player's don't
) but I found it rather intrusive in actual play. It broke my Referee-ing stride and players calculating DMs seemed to distract them from actually roleplaying.
It encouraged thinking of what the mechanics allow, vs. what a character would choose to do, given their character. I also found it more cumbersome to track what skills players had (resorting to elaborate spreadsheets, actually) - even as a player I would forget from the list of 20 or more skills for older PCs. CT characters tend to have very few skills.
Also, MgT makes a lot of use of 'level-0' skills - encouraging rolling for more mundane things.
MgT combat is better defined and more featured, but a lot less deadly to the point of absurdity in many cases. A bit more simulationist than how I play CT combat - which is not by the rules - but I took away some nice ideas from it.
MgT space combat is a bit better than CT, IMO - so I snagged a number of ideas from it. (Ignoring capital ship combat ala High Guard books in both.)