Master Servers

I'm into, a multiplayer game, where I have learnt, how to code. But, don't know anything about Master Server and all. Read the documentation, didn't seem to understand it completely. Also, in the M2H networking tutorial, FPS example, is made by unity's official master server. Why can't we use that, in our games??Any reliability issues??? What could go worse??
Are there any perfectly working examples, out there??

Please do, clarify, or point me, to somewhere, where I can get detailed information.

Thanks in advance

 

you can use the master server if you want.

but you might missudnerstand what it is: Masterserver etc only offer you game listing and NATPunchthrough
you can't run your games through it or anything alike

 

Thanks, but some threads seems to tell me, that unity's server has some problems..Can you fill me in on that??