I had my first session two weeks ago, as I wanted to wait and see what happened before posting my first experience!
The laser stings a teeny bit, but nothing too bad, and it has a fancy air attachment that blows cold hair onto your skin at the same time, which was very soothing. But the pain really isn't much at all, and doesn't last long. I was having my underarms done and I was in and out within 5-10 minutes.
You come with shaved skin (they have razors if you have been unable to or have forgotten), and you can remain clothed if you wear a vest (or whatever the area you're getting done).
Two weeks on, I definitely notice an impact! I'm not getting stubble after shaving, as each day the hair is eventually falling out. It has definitely killed a lot of my hair, which is exciting. Hair grows in cycles, so a lot of this hair will grow back in its next cycle, which is why you need more than one appointment. I'm not sure how many I'll need to have. I've got my next one in about 7 weeks time I think. So watch this space!
It's definitely more of an impact than my first IPL, which is exciting!! Whoop!