Almost all ISV's have to consider the 'SaaS question' at some point in time.
The SaaS question is a big issue and is as much a commercial concern as it is a technical concern. It is also a matter that justifies looking for an external IT services partner, both to provide specialist advice and to deliver cost effective 'heavy lifting'.

ZSL's preferred method of engaging with ISV's is therefore via a feasibility study, designed to bring together the ISV's technical and commercial people as well as introducing ZSL SaaS specialists into the discussion.
The ZSL SaaS feasibility Study normally lasts 2 - 4 weeks. The deliverable is the SaaS Feasibility Study Report, to provide the information necessary to support the ISV's go/no-go decision.