GDI. I prefer armor, firepower and quality over speed, stealth and quantity. After all, nothing says GG better than a bunch of Firehawks bombing the crap out of your base, then getting shelled by Juggernauts and finally a pile of Railgun Mammoths
Everyone has their faults, but it's how one confronts and changes them that matters.
I think something beats that: the fact that i got 3 shadow teams on your base pacing beacons to bombard it and you cant even notice it. Then i nuke your base and whit the same beacon i destroy what remains of your MCV and now, powerless, and unable to build power plants, you are DONE
GDI, but as long as we are talking about favourite factions, I own you all when I eat up your forces with a full Scrin invasion force, Storm Riders destroying all you hold dear, as Carriers eat up your veichles and structures, and warships fly in to finish the job. Then if I feel like messing with you, I leave your cripple sad base alone so a Mothership can come and have some fun with it
I WILL RULE YOU ALL WITH AN IRON FIST!!!! MADE OF TIBERIUM!!! yes FEAR THE IRON TIBERIUM FIST!!!! and if that doesn't work, THEN I'LL CARRIER RUSH YOU! HA HA
While their methods seem brutal at first, they are the only faction with a coherent plan for dealing with Tiberium, embracing it and it's inevitable takeover of the planet. GDI has no coherent long-term solution, trying to treat the symptoms, not able to deal with the cause.
Their characters are also professional, I've never liked Michael McNeil, and it seems the developers of Firestorm didn't like him either, killing off in the crash of the Kodiak (sadly, he was later resurrected for the novel and Tiberium). Anton Slavik and Oxanna Kristos were true professionals.
I like to use GDI units because they are more conventional and easier to manage. Story and character-wise, I have always supported NOD. Not that I prefer a Tiberium future, but given the superiority of the Scrin, Kane's solution maybe the only solution. I especially like the devote believers of NOD, but their faith has been waivering since Anton Slavik's death.