Must-Have for most downloads. Rated 4 out of 5 stars
Overall, great add on, a must-have. However, does not work reliably with MP4 files with FireFox 23.0.1 on Intel Macbook Pro OSX 10.7.5 and up. Most of the time gets 416 errors. If you need to download MP4, then you will need another solution as well.
Even with the MP4 problem, it is still the best download manager, in my opinion.