(Re: It was loud enough for me but I think it's a personal thing. I was going to try that Hella one too. For what 15 bucks I'd give it a shot. Tell me how you like it if you go for it.)
Since you asked...
I installed the Hella horn today, and it is much louder, and I'm very pleased with it. While the other horn that I ordered from TVA sounded cute, this one is much louder and has more attitude. It's rated at 113 decibels. I'm not sure what the TVA horn was rated. I actually wondered if anyone would hear the TVA horn to avert an accident, especially in a traffic situation.
The hella horn is larger, and just heavier duty and better built...and still has the Beetle sound.