At one of the projects I did in Chicago, we were using HP Service Virtualization product to emulate functionality of coupons.com. It was working absolutely fine until one day when HP SV was upgraded. Since the upgrade it became a bottleneck during our tests. Under load virtualized services were taking several seconds to respond back. Ticket was created and escalated to HP engineers, they traced the issue to javascript engines, the issue was never satisfactorily resolved and it kept coming back.
At the same project we were using some Cavisson products, I had never heard about Cavisson before this project. Cavisson engineer at site when learnt about our problem was quick in getting one of their service virtualization product arranged for us. It was an easy switch for us environment wise, we had to simply change the end points. With Cavisson Service Virtualization we were normal again and our testing continued in a stable manner.
HP was a far bigger and greater company but Cavisson with its quick service and stable product was able to outpace them.