I tested Jupgradepro because the siteground tutorial. But the tutorial is made with a simple joomla 1.5 website, and in my case i have a very big 1.5 website.
I had some problems in migrating, but the support was excellent.
I'm a newbie in this matters, but the support have the patience to help and resolve the problems of my case.
I think all 1.5 joomla websites are very different, so it's difficult to have a 100% solution that works for all.
I rated excellent! because the support was excellent and fast to find solutions.