In this industry like many people are know it all D&%KS. You will see and hear people bad mouth other shops, drillers, manufactures, bowlers ect ect ect ect.
If you come across it, I'd go else where if possible. In sales the number one thing to remember is not to talk down other anythings, but promote and compare whatever it is you have that your trying to do.
Promote your equipment, your services, ect. Because it is easy to talk down something but then when you one day start selling that product it will be a lot harder to explain why it is no longer a bad thing like you had said before.
Back to the original point, many of the people you come across are " know it all D&%KS."