I've had laser hair removal on my legs, underarms and bikini line, paying for a course of 6 sessions per area. After the first session at least 80% of the hair was gone, but not all hair follicles are active at the same time, so it is important to go back and attend all the sessions, usually between 4 and 6 weeks apart. I had my hair removal done at cosmetic clinics by certified doctors using medical grade lasers, which target individual hair follicles and are incredibly powerful (and almost completely pain free). Do be aware that no hair removal is ever completely permanent. After a few years, you may find that you have a few, soft, downy hairs reappearing, in which case it might be necessary to go for one or two top up sessions.
Beware of having hair removal done by beauticians at salons that offer IPL hair removal (Intense Pulse Light) rather than targeting individual hairs - IPL just blasts the laser over the entire area and is far less effective (not to mention more painful).
Laser hair removal can be expensive, but I've always paid for mine through deal sites such as Groupon, Living Social, Wowcher etc, so it's worked out as £99 per area, as opposed to the £500 - £1000 they charge normally,
I couldn't recommend laser hair removal enough - no more razors / waxing / tweezing - it saves so much time and stress!
I've never needed to have the treatment done on my face so I can't comment on that, but I can't imagine that the experience would be much different from that which I've detailed above.