An someone tell me the difference with the Picoway and he Picosure laser and now are they compared to the Cutera Enlighten?

The differences have all to do with wavelength, power, and pulse durations. They all have picosecond capabilities. All but the Picosure have nanosecond as well. All but the Picosure have 1064 and 532 wavelengths. The Picosure is 755 which is best for greens and blues, but not so good for everything else. It also has low power, so smaller spot sizes need to be used. When small spot sizes are used, the risk for scarring increase because the heat doesn't penetrate as deeply. The Piqo4 has the highest power of all these lasers with the Enlighten the next most powerful. There are dye kits associated with the Piqo4 to get other wavelengths as well. I believe the Enlighten has a wavelength in the 600's which was added recently and is not will all machines. The Picoway wavelength which makes it good at the blues and greens now. With dark skin types such as yours, the 1064 is essential to protect the skin from laser damage.

Pico refers to the peed of the laser. a pico second is equal to an amazing one trillionth of a second! a nano second is one billionth of a second. This is important because the faster the speed the more energy you can deliver with less damage to the skin. Pico is the current standard of care. It is particularly helpful as the ink lightens and the smaller remaining particles are difficult to remove, pico cleans these up.
Having darker skin the speed of the laser is not the issue but rather the wavelength. Lasers aim at color as your ink becomes closer to your skin color there is greater chance of injury. Certain wavelengths are more apt to cause discoloration of darker skin. for example you would not want to use a 532 wavelength laser (good for colors) on your skin but it would be fine for caucasian.
Using a 1064 laser works well on black ink and is safe on your skin. most newer machine offer at least 2 wavelengths.
Good luck!

All three of the lasers you are asking about utilize pico technology. Pico lasers fire a high energy, short duration pulse (pico second). Older lasers can not do this. Pico lasers are very good at removing tattoos and are generally safe on darker skin because of the pico second pulse. The three lasers you are asking about are not all created equal. The Picosure has the lowest energy capability and some of the older models just can't remove black ink. The Picoway has three wavelengths and can generally remove all colors of tattoo. The Enlighten also can remove all colors of ink and has the most power of the three lasers. If I had dark skin with black ink, I would go for the Picoway or Enlighten.