I'm interested to hear the discussion surrounding the value of Gi training for self defense compared to the value of No-Gi training for self defense. Keep in mind this is in the context of Brazilian Jiu Jitsu, but it can apply to other martial arts that use the Gi like Sambo or other martial arts that do not use the Gi like wrestling. It's more of a grappling discussion, so it's leaving out the obvious combinations like Mixed Martial Arts contests, Pankration and Combat Sambo.
My take: A skilled player of a grappling based combat sport possesses the defensive skillset necessary to emerge victorious regardless of whether they are a gi or no-gi specialist. I feel the distinction is overblown and can be overcome with a very small amount of training required for adjustment.
Case in point: Brazilian Jiu Jitsu Gi player extraordinaire and overall nerd Mikey Musimeci just won a high level No-gi match with a #1 ranked No-gi player and 10th planet (a no-gi school) phenom Geo Martinez. Yes it was a points victory, but it was decisive, with Musimeci putting on a clinic on Martinez, who as a 10th planet black belt, has trained a very small amount of Gi, compared to Mikey, who has a highlight reel in the Gi, but relatively fewer highlights in the no-gi.
If you're in a colder climate, of course, the winter time will favor your Gi style techniques...especially if your school emphasizes high amplitude Judo type takedowns. But I gotta think a strong cross collar choke can still be made to work. But then the average no-gi guy probably at least considers training for the ADCC ruleset, which emphasizes submission attempts in the first five minutes of the match (which have no points) then when points kick in later in the match, the guys with strong wrestling or counter wrestling skills will see more success, as things like guard pulling are penalized. And I think wrestling is possibly one of the greatest martial arts for self defense because it emphasizes holding a position of control for a long time, which can be useful for if you are waiting for the police to arrive. You just tie the dude up, take him down, hold him down, sprawl him out and wait for the cops.
Of course, I believe these need to be supported by a sense of weapons retention (if you're armed) and solid striking skills either way, but I feel like those things don't need to be exceptionally complex. Just well thought out.
So who likes the Gi and who likes the No-gi? Any particular reasoning for it? My school trains both (as well as striking classes) but I find I actually like No-gi a little more, reason being I'm not very good at leg locks, and it makes me focus more on wrestling, top position and hunting for strangles. I don't mind Gi, though. I just don't play that lapel guard stuff.