Optimizely - A/B testing you'll actually use.
Adobe Target - Adobe Target provides an intuitive user interface and an expanded personalization toolset.
Webtrends Optimize - Webtrends Optimize - a powerful, enterprise-grade Testing and Personalisation platform. AB, MVT & Server-side Testing, Product Recommendations & much more.
invesp Pii Testing Engine - invesp Pii testing engine offers A/B testing solution for site optimization.
Evolv - Evolv is the visual editor for web-based projects that are used to find better ways to connect with customers in order to improve marketing economics.
Experiment Engine - Experiment Engine is a A/B testing solution that harnesses human expertise to automate conversion optimization.