I have a 1.5 site and was a bit worried it wouldn't work. It is superbly written, does exactly what it says it will do and is BY FAR the best thing I have found in the Joomla world. A superb product.
And the support is unreal - answers within 30 minutes. The other day up to midnight! They come back with animated screenshots showing you exactly what to do. I have never seen this before in 18 years of designing. Absolutely fantastic service.