I stopped wearing sleeveless shirts because my armpit hair grew very quickly.  I would shave in the morning and have a 5 o'clock shadow by the end of the day.  I also didn't like that when I did shave, my armpits still looked dark because the root of the black hairs were still visible under the skin.  I was so self conscious because of this :(... so I decided it was time to zap it all away. 

There so many lasers to choose from, but I ultimately chose the Tria Hair Removal Laser 4X for a few reasons:  Tria uses a diode laser which is the same type that would be used at a spa.  All of the other options were IPL lasers (like the Silk’n Sensepil), and would require purchasing replacement bulbs.  I've been burned many times in the past with products that required replacement parts, only for them to be discontinued.  I don't want to be stuck in that situation again.  

Also, the Tria 4x Hair Removal Laser has a life of 200,000 pulses, whereas one cartridge of the Silk’n Sensepil Permanent Hair Removal laser is only 1,500 pulses.  I figure the 200,000 pulses without having to buy bulbs will be more than sufficient for my needs.  

As far as my "stats" are concerned:  I have thick black hair on tan skin.  My MAC Shade is NC37 but if I were standing in a drugstore looking for a foundation I would most likely go for something that says "Light Medium" or "Light Medium Neutral".  If you need a visual guide, I would say that my skin tone is similar to Eva Longoria's.  Hope that helps!

PREPARATION
I would shave about four to five hours before using the Tria Hair Removal Laser 4X.  That way my skin is less sensitive from shaving, but also doesn't allow for enough time for stubble to appear.  The trick is to get the laser to target the dark root under the skin.  Otherwise, the stubble will simply burn and be more painful.  I also used the Tria Hair Removal Laser 4X on a weekly basis (thinking back; I believe results may have been even better if I did it every two weeks per the instructions, but I was impatient).

Check out the before and after pictures.  It WORKS!  I didn't know what to expect because most of the reviews were for dark hair on pale skin, but I'm happy to say that it worked on my tan skin as well.  The above results took 150 pulses per armpit, per week, for 12 weeks.  The first four sessions were on setting 2 of 5, then the rest were on 3 of 5.  As for the battery life:  It was okay.  I put it to charge after every session so it can be ready for the next session.  I would say the battery lasts for about 400 pulses (depending on the setting).  I can't imagine using the Tria Hair Removal 4X on large areas like your legs though.  The treatment window is only 0.375in (1cm) across so it would just take forever, and you would have to charge midway.