I'm the founder of Visual Website Optimizer. While Optimizely is strictly A/B testing, VWO is a much more comprehensive testing tool. In addition to A/B testin

I'm the founder of Visual Website Optimizer. While Optimizely is strictly A/B testing, VWO is a much more comprehensive testing tool. In addition to A/B testing, we support Multivariate testing, Split URL testing, Heatmap/Clickmap, Targeting/Segmentation and Revenue Tracking. VWO is being used by companies that have sophisticated and comprehensive testing needs (like AMD, Microsoft, Groupon, etc. and thousands of SMBs) That said Optimizely may be slightly easier to use but with VWO our focus is on both: comprehensiveness of feature set _AND_ ease of use. Since both companies offer free trials, best is to signup for both of them and see which one is better suited to your needs.