My cat published this one before it had any body text. I'm sorry about that (the cat is not).
Readers of my recent posts comment threads may note a number of favorable
thoughts on Classic Traveller, at Mongoose's expense. In the Core, Mongoose did a lot of abstraction away from CT in things like armor handling and starship combat. In the supplements, Mongoose has put many poorly-edited, poorly-thought-out subsystems that don't work well in play, along with a vast number of superfluous careers that don't add much to the game
However, a discussion with Tim about ACKS vs Traveller led me to the realization that MgT is very well-designed in one respect besides that it's subtly balanced. The context was the general complaint that ACKS has encouraged me to go Hard Simulationist - the fault is my own that I do my best to simulate a world to the maximum extent supported by the rules, but in this case it has been the undoing of my games for the last year and a half. MgT, in comparison, has a number of rules that exist in support of coherent narratives - Contacts, Allies, Enemies, Rivals, the Connection Rule, the Skill Package, and Patrons all spring to mind. Most of these help take Traveller's random character generation and use it as a springboard for an emergent narrative, and of this set, only Patrons were present in CT. So I have to give Mongoose credit for that - they took a strongly simulationist / gamist classical system, and grafted a small set of narrative-supporting mechanics on top in a way that felt organic and played well (I distinctly recall that those were some of our favorite rules in actual play in MgT).
What's more is that these mechanics are largely associative. When we think of narrativist mechanics, I typically think of action points / willpower / conviction-type "win button" mechanics which permit the players to keep the story moving in the direction they favor, or of Wushu-style action resolution mechanics that are primarily narrative-driven. As Justin Alexander noted back when, these are both dissociative; they treat the consistency of the game-world as inferior to an outside force, the narrative, which behaves in a manner most inexplicable to the characters. MgT's mechanics, while also operating in support of the formation of a coherent narrative, do so from a completely different angle - rather than "X would be a coherent narrative; make it so", they provide a palette known to both players and GM of elements that could sensibly exist within the world and which, when used judiciously, tend to produce a satisfying narrative. Meanwhile, they also ground the PCs in the universe, alleviating Drifting Murderhobo Syndrome. They're simultaneously simulationist and narrativist, and that's somewhat remarkable in a rule.
So I think that's part of why we've had so much fun with MgT in the past - it nicely supports simulationist (world ecologies), narrativist (connections and rivals), and gamist (starship loans, trade) play within a simple, mostly-well-done core. "A good all-rounder", I suppose.