Modeled with Blender 2.71 , rendered in Cycles 4000 samples. Used the Versaille absinthe glass as reference! Image is still a bit noisy, I tried to remove some noise with Photoshop. Comments are welcome!
Your modeling and lighting is great! 4000 samples, though, seems a bit unnecessary—you should be able to handle this scene with 2000 or less. What do your sample settings look like?
Also, the noise could be a result of a number of things, not just sampling. Try some experimenting to see if you can pinpoint what’s causing the issue.
Thanks for your comment 
I used more or less the default light path settings, with filter glossy : 2.00 . I’m not very good at optimising the settings so I used 4000 samples just to be sure. To be honest, I always thought cycles has trouble with rendering glass.
Check the clamp values, 5 and 5 are good for remove noises. Then check the light path and experiment.
By the way I like the glass model 
Keep up the good work!
I think you’re right to a certain extent—I’ve done a lot of work with the Cycle’s glass shader, and although it’s improved over time I still see it falling short of similar render engines like Vray, Octane, and Arnold. Of course, it’s unfair to directly compare Cycles to these engines because they all approach rendering differently, but I’d love to see some love go toward the glass shader in Cycles.
