Never used anything like that (yet to install the air horn I bought my cousin). But I would guess that would be pretty damn loud. Are you looking to get away from a stock style horn or just want something that would hurt the pocket?
I'm sure it will have plently of pizzaze in how loud it would be; but I'm sure that novelty will wear off quickly if that is your normal horn. I can't speak of if they is a delay or not with these airhorns but I can't see why there would be much of one. I also doubt that it will go for a set amount of time then stop playing.
Maybe if you have a yard near by just go and try to grab a horn out of some other GM car.
That horn is not a musical horn. It is instant BTW. I had a double horn like that on my truck and used it in conjunction with the oem horn. Only reason why is that I wanted to make sure people heard me when they cut me off.
If was really loud too, lol. But mine was not a deep enough tone for me.
I do also have that dixie horn that I installed on my 69 GMC pickup, at least it did suit a 69 pickup but not a newer vehicle.