Well it's not the most comfortable and I felt no real benifit from it.  But I'd say that it's one of those things you have to try once just to say you've tried it.

I would say go for it!

The first cup hurts, and the pain gradually goes away with more cups on your body. It feels weird afterwards but if you do it late at night then go to bed, your back is still a little numb so it's great for sleeping on these hard beds in China!

I'm not in Beijing, so I can't help you with that one.

But, I am a qualified TCM practitioner from back home, and I've done cupping lots of times, and seen it far more. Depending on just how much of a flame you get will depend on whether it hurts or not. Lots of flame, more uncomfortable. Rarely should there be much 'pain'... not much different to just putting a vacuum on your back (or other parts, depending!) You can also get a minor burn if the flame gets on the edge, and thus heats up the glass edge that goes straight onto your back (it shouldn't, the flame should only be inside the cup!)

Benefits? You probably won't notice benefits straight away, nor probably even the next day (when you still have all the bruising). But, after all that bruising is gone (which can take a few treatments), you should feel a lot more freedom and flexibility in your movements. You may even notice that you feel healthier in general.

If you're really worried about it, there are also plastic suction cups, where they actually withdraw the air like using a syringe... that way, the amount of air left in them is easily regulated, and thus the amount of discomfort can be minimised.

Give me the money and I'll do something useless instead. 

used it a few times to keep the wife happy
But no bennifit except I can claim my wife beats me

Mumbo jumbo IMHO.  So no....

If you want to be covered in giant hickies, there are more fun ways to accomplish that.

thier  is no pain and its suppose to bring out the bad toxins

You should try it, but not sure where they do it...actually some of the places near JC should have that going on. DOn't know the exact address but it's close to the newly built JC.

It won't work unless u drink some bear bile and cobra blood at exactly 8 minutes and 8 seconds before and after. During a full moon facing east praising those who have gone before you.

In other words, cupping is for Fools. When I see young children with those bruises I wish the responsible party would be charged with child abuse. Just so you know, foot-binding isn't such a good idea either. 

Did it once. 

Not painful and did nothing except cause welts along the back for a few weeks. Just another item ticked of my list in China