Latex or non latex condoms?

Is a latex condom better than a non-latex condom as a contraceptive?

The non-latex condoms are used by people who have allergy to latex. There are very few studies on the different condoms and their efficacy as contraceptives. But some non-latex condoms like eZ do not prevent pregnancy as well as latex condoms. In general, the non-latex condoms tend to break more often than latex condoms. Overall, most partners prefer non latex condoms.
My feeling is that non-latex condoms are overpriced and are only useful for people who are allergic to latex.