A Super Robot piloted by a hot-blooded male who screams his attacks. Over-the-top action paired with serious drama. Victories, tragedies, love, betrayal, personal struggles, a fight to save humanity. You'll laugh, you'll cry, you'll cheer. Highly recommended.
To truly understand the meaning of gar and all of its various connotations relative to man, both TTGL and G Gundam are excellent starting references. Both have dramatic combat, giant robots, allies that become enemies, enemies that become allies, and a hero that goes out there to fight for what they want. I hate to alienate any populations by saying, this, but speaking as a man, to men, you should definitely place both of these on your "must watch list".
Consider G Gundam as the older version of TTGL. I think that G Gundam has a better storyline than TTGL, but at the same time the story moves at a slower pace than TTGL as well (being 49 eps vs 27 eps respectively). Still, if you liked TTGL than you may want to watch G Gundam as well.
Like others have said before, G Gundam is like the 90s version of Gurren Lagann. Both protagonists have older brother figures in their lives, whose presence is absent for the majority of the series, yet influences most of the main characters' actions. Both shows have a large, likable cast, all of which the members of have distinct personalities. Each episode is jammed packed with action-packed battles with cool-looking mechs and hot-blooded pilots ready to kick ass.
It's most likely if you enjoy one, you'll enjoy the other.
The Gundam series most similar in tone to Gurren Lagann, at least in terms of OVER THE TOP RIDICULOUS BATTLES AND DUDES SCREAMING THEIR ATTACKS.
Seriously, G Gundam is tragically underrated. Please give it a try if you can find it, it is worth your time.
Both series are essentially about giant mechs fighting to the top. While the goals are different, the base premise is the same, fight against overwhelming odds and win by screaming loudly and launching loud powerful attacks, with you having to turn your brain of and scream alongside with the protagonists as they destroy everything. Gurren Lagann is just as over the top and epically absurd as G Gundam, but pushes it even further with huge explosions, over the top finishes, and robots bigger than anything. If you loved G Gundam, you'll love TTGL, and maybe even vice versa.