I tried to get jUpgrade working for weeks with unanswered forum replies and seeing may other people having the same problem as myself with no answers. I read about this solution and gave it a go and what do you know we were migrated first shot. The site is massive so we ran into a couple of issues but worked with support and run much better. Still not perfect but we are migrating large volumes of data so understandable we have to take additional steps but with each release I am seeing improvements. If you want to migrate your site right this is the solution for you.