Fraxel is a non-ablative erbium laser which varies from the fractionated CO2 laser in wave length. The fractionated CO2 laser delivers a more aggressive treatment in less treatments at higher strengths. Since less treatments are required, the higher strength results in longer down time period, usually ~4-5 days. Fraxel requires more treatments at a lower strength and a shorter downtime of ~1-2 days. Fraxel is safer in all skin types and the CO2 laser is best for lighter skin types and Asians. Both lasers have shown to beautiful results for wrinkles, acne scarring, and pigmented lesions.
Fraxel or Fractionated CO2 lasers treat skin in a segmental manner where the laser leaves untreated skin in between treated skin to allow the skin to heal much faster. This leads to less downtime and less risk for complications. But you always have to remember that the more aggressive you are the more results that you are likely to get. With the less aggressive fractionated laser, you are going to get less results and are likely to need more treatment sessions to give you the same results that you would received with the more aggressive approach. For some people this is a great option to have less down time so they can get back to work earlier. So it depends on your lifestyle.