They are thinner and twice as strong as latex, and they are odorless and flavorless. They also transmit heat better than latex and are more resistant to heat and light damage. In addition, they do not have the proteins in latex condoms that cause allergic reactions in some people. Unfortunately, polyurethane condoms are more expensive and do not come unlubricated making them useless for oral sex. This is an outrage and you should write your congressman immediately.
Many people seem to be experiencing breakage with polyurethane condoms.
This is probably because they are not as elastic as latex. If you are not very experienced with condoms, you may want to avoid polyurethane condoms unless you have an alergy to latex. If you use this type of condom, be sure you have plenty of lubricant. If you want to try polyurethane, look for Avanti and the Reality Female condom. The Wet Spot only recommends natural skin if you are in a mutually monogamous relationship, you have both tested negative for STD's, and you can be absolutely certain one of you is not going to go out and catch something.