I carry a Glock 30 also, and I have three holsters for it. They're all paddle holsters, since I have to disarm to go inside a couple of places on a daily basis.
My favorite is from iTAC. It's a kydex holster that's adjustable to virtually any angle. The gun locks into the holster and is released by a button along the side, right where my trigger finger goes when drawing.
I also have a Blackhawk Serpa. This can be worn as a paddle holster or a belt holster, though Blackhawk now has a line of Serpas that only come with a paddle. It also has adjustable cant, but fewer angles, and it has the same kind of button release as the iTAC. The fit for this holster was a bit snug for my liking.
Both of these holsters were actually made for the Glock 21, but will accept a Glock 30. This makes for a longer holster that is a little harder to conceal, but the excess can be cut off.
And I have a Desantis Viper. It's a leather holster, with adjustable cant and a thumb break, that is built for the Glock 30. I like that it is the correct (shorter) length and that it rides a little high — both things make it easier to conceal.
My personal reason for preferring the iTAC is that, once the button is pressed, it releases more easily, which makes it quieter. I want the option of being able to remove the gun quietly in case something is developing but I haven't been spotted by the BGs yet. Such as someone robbing a store where I am shopping. I'd like to be able to draw without attracting attention so I can protect myself if I'm overheard using my cell phone. Your priorities may vary.
"An armed society is a polite society." — Robert A. Heinlein
"After a shooting spree, they always want to take the guns away from the people who didn't do it. I sure as hell wouldn't want to live in a society where the only people allowed guns are the police and the military."
— William S. Burroughs