Are specialty condoms like ribbed ones or flavored ones less safe?

Flavored may have some chemicals, but I don't think any of them are less safe at preventing pregnancy. Just make sure they're not marked as novelty condoms. Consumer Reports did a rating scale of condoms a while back, and Trojan Ultra Ribbed Ecstasy made a perfect 100 along with 6 other makes. I think a lot of them were ultra-thin as well... I don't recognize some names right off the bat.