It's your classroom; use what you are comfortable with. Like many I
have been on all sorts of different platforms. We build our own PCs
here, so I use PCs in my lab. The nice thing about this is I know
exactly what software is on the machines down to the drivers. We had a
Mac lab that just wasn't being used, so no more. But I have colleagues
at Mac schools that had a PC lab that wasn't used.
Why don't you survey your students? Or if you have local industries that
you feed into use what they use.