I would highly suggest starting out with a Florida or Tropical gar first. You can learn the ropes with these a bit easier than with a Gator. Gators and Cubans are somewhat demanding fish and are not the best to jump into first.
1. Listen to him, he's kept/dealt with gar longer then most of us here.
2. Read the stickies.... they cover a wide range of basic gar husbandry includeing gators.
3. have a large indoor/outdoor pond that will be dedicated... gar don't always do well with tank-mates being realistic that they are your "top priority" in the set-up will make housing/tank mates/ect all easier and successful.
I started with a florida gar... he was a great hands on learning fish to help graduate me into the more harder to keep/care for species. I have yet to aquire a true spotted gar or a shortnose gar... but Gators are not on my list... I simply do not have the room to house one of these beasts. I envy you guys with outdoor temps to accomidate them in ponds ect. And imo realistically that's what your looking at if you want healthy gators. Your looking at a fish that will rival the needs of an Ariapima... surpasses a RTC ( my hybrid cat is childs play compered to what my gar can do and they aren't much bigger atm then he is) .. And can be as food aggressive as anything else in the water ( It is not uncommon for them to comm well with other big fish then miss a feeding.. and there goes a tank-mate.. heck it happens with the less aggressive species)
Keeping Gar in general is unlike any other fish I've kept... not better or cooler... just different. They aren't cichlids, or catfish, or rays... imo they show a level of intelligence/capability that does suit their closely related namesake.. only when I've worked with crocodilians did I see a "similar" brain. Not the same but in many ways similar.