I'm using a Johnson's for my rack. I got it prewired from reptile basics for 80. shipped and got it 2 days! yes there is an audible click. since it is on the other side of the house from my bedroom, I don't hear it much, but I cna see how it would get annoying if it was in my room.

next year I'm building my incubator, so I will be lookin at getting a herpstat.