An excellent WebmasterWorld thread named Top 3 PPC: Where does AdWords Rank for You ranks the three top players, Google AdWords, Yahoo Search Marketing & Microsoft adCenter against each other. The ratings are broken out by (1) Traffic Volume, (2) Quality of Click, (3) Ease of Use, (4) Lowest Cost per Conversion, (5) Technical Support, (6) Has the Options for Your Needs, (7) Versatile and (8) Overall Rank. We have a nice amount of responses so far, but I would love to see more, currently, here is how they rank.
G = Google, Y = Yahoo and M = Microsoft. Each letter represents a vote for that slot. Ties are represented /.
(1) Traffic Volume: #1 G G G G G G M G G #2 Y Y Y Y Y Y Y Y Y #3 M M M M M M G M M (2) Quality of Click: #1 M M M M M M M Y G #2 G G G Y G G G G M #3 Y Y M G Y Y Y M Y (3) Ease of Use: #1 M Y G G G G G G G #2 Y G Y Y Y M Y/M Y M #3 G M M M M Y X M Y (4) Lowest Cost per Conversion: #1 M M M M M M M G G #2 G Y/G G Y Y G G Y M #3 Y X Y G G Y Y M Y (5) Technical Support: #1 M Y G Y M Y M G Y #2 G M/G Y M Y M Y Y M #3 Y X M G G G G M G (6) Has the Options for Your Needs: #1 G Y/G G G G G G G G #2 Y M Y Y M M M Y M #3 M X M M Y Y Y M Y (7) Versatile: #1 G Y G G M G G G G #2 Y G Y Y G M M Y M #3 M M M M Y Y Y M Y (8) Overall Rank: #1 G M M G M G M G G #2 M Y/G G Y Y M Y Y M #3 Y X Y M G Y G M Y
Forum discussion at WebmasterWorld.