Hi there!
Currently I'm learning Maya 7.
Very cool 3d package indeed!
I tried to render some glass materials as photo realistic as possible with Mental Ray.
The left glass turned out a bit thick, but ... I don't care

Comments and critiques are very welcome!
Techniques used:
Final Gathering, Caustics, Image Based Lighting with HDR Images, etc ...
Materials used:
Dielectric, Lglass, Reflection Utility, etc ...
Rendertime:
2 to 3 hours
Fantastic job! Keep it up!
1. make your liquid very slightly intersect with glass, so from outside it fills the glass completely and doesn't leave a gap from liquid to outer glass (check a real filled glass for reference)
2. dielectric is nice, but i'd give a try to mia_material_x with preset, Physical glass.
3. check the IOR for glass and liquid, differences between them makes it more realistic.