We're a pretty busy web department for a small advertising firm, and we rarely have time to write reviews like this, but I felt we absolutely needed to write one for this tool, because we would have been dead in the water without it. We were faced with the task of moving 10 old Joomla 1.5 sites done by a previous developer to a new hosting server (which eventually turned out to be upgrading them as well. There were 2 reasons for this move - 1) the sites kept getting hacked and 2)since we were now inheriting the sites, they needed to come over to our hosting plan. Because the sites kept getting hacked, we also recommended upgrading to the latest version of Joomla, obviously. And, it turned out, we wouldn't have had a choice in the matter anyway, as our hosting platform runs PHP 5.4, which evidently doesn't support Joomla 1.5 (which we found out upon initial loading of the new sites). Then the REAL headaches started to manifest when we searched at length for the best way to upgrade Joomla 1.5 to 2.5. Not only are there very few tools out there for this purpose (2, really), but Joomla itself has no formal documentation or recommendations on this matter !(unless you want to struggle comparing the differences in the new db schema and reinserting/manipulating all of your old data to fit the new schema). Oh, and by the way, good luck finding anything even detailed on the exact differences between the old and the new database structures! So, our only choice was one of the plug-ins - either JUpgrade (the one recommended in Joomla's documentation) or SP Upgrade (which we found by doing our own searches - when it really should be in the Joomla documentation too!) JUpgrade operates by running on the same installation as your 1.5 and upgrading to 2.5 from there. SPUpgrade operates on a fresh new Joomla 2.5 installation and migrates your database from the old 1.5 source. Well, turns out the old host running these 10 sites was on PHP 5.3, which can't run Joomla 2.5! Our new host has PHP 5.4, which can't run Joomla 1.5! What a mess! So, we were down to only 1 solution - install a fresh 2.5 on the new host, copy the old 1.5 db over to the new host, and install SP Upgrade and just pray. Well, it worked! After days of research, playing with code, fidgeting data - this just plain worked right out of the box! Gotta say - that rarely happens, especially with Open Source! And even when I had a question, not only were they able to help, but they also answered quite promptly (and we're in the US, and I think they might be in Greece?). All in all, I was mightily impressed and this tool definitely warranted skipping my lunch break today and writing this review!