Jesse from Apprenda gave me a tour of Apprenda's new solution - the SaaSGrid, a new platform reaching out to ISVs who want to move to the SaaS model. According to Jesse, SaaS grid is distinct from Force.com and Quickbase because they offer a constraint free PaaS to ISVs.
I found their SaaS billing function the most interesting feature. Their billing function allows users of SaaSGrid to charge for individual functionality and features. In my view SaaS Grid's platform will allow .net ISVs to move from on-premise to a multi-tenancy, hosted, subscription based provisioning of software in a breeze.
I think they are up against tough competition with established players like Quickbase, Force.com, and startups like Coghead and WyaWorks, so I wish them the very best.