Hey, and welcome to the 3d world
The watermark has to stay in Maya to keep it legal, until you fork over an unreasonably large amount of money for the full program (this is my own opinion, and I am one of those that did it anyway )
Still, I remember my first stuff with PLE, and, frankly, after 2 days MayaPLE.exe was somewhere in the recycle bin .
Mental Ray is a rendering software, a program that takes what models you make and renders them in high quality at arbitrary resolutions, the sky's the limit. Mental Ray does come with every shipped version of Maya. It's a very powerful tool that takes a very long time to master, but is very efficient. I am not a master at Mental Ray, so I use alternate renderers, programs that do the same thing as Mental Ray. Still, what work you've shown is very very good for 2 days in.
Cheers and welcome again to Simply Maya
-Matt
Live the life you love, love the life you live