I haven't eaten there, so can't answer your question, but you might want post over on the Universal thread, since that's where the Hard Rock Cafe is. There is not one on Disney property. Here it is: http://disboards.com/forumdisplay.php?f=30
And if I remember correctly, you only get to keep the glass if you pay for it I've been to the one in Boston and in Foxwoods several times, keeping the glass is an additional charge.
The food there is good, nothing spectacular. But I go for the fun, not the food.