Thanks Mark for the reply.
I would be getting the MINT software that Tim Ward mentions so I would have the shared projects of the ISIS. So that levels the playing field a bit between the two options.
I think my editor would be more happy about using the ISIS just because he has used that before.
I am still most keen on the Small Tree option and with the support of my reseller here in the UK and Small Tree in the US hopeful I will be fine and the benefits of owning the system will work out in the long run.
Bill