They're ugly if you can't hide it and that matters to you.

If you get one, don't try to half-ass it by just plugging into the horn wires, you'll either blow a fuse or damage the horn. You need it wired to the battery with a fuse and relay.

I have a generic Stebel nautilus clone that's better than the original. It's loud as fuck so I use a very quick tap unless I really need to get someone's attention. Will echo what another said, a relay is a necessity.

For any compressor based horn, try to mount it somewhere where it doesn't ingest water and dirt.

My friend has a Denali sound bomb. It sounds like a train horn. He likes it.

Just put one on my Multistada. Haven't been able to go for a ride yet, but in the shop it was loud AF. Mine is the split one, so I mounted the compressor where my evap canister used to be and the horn in the stock location