I'm going to give the generic non-comittal answer: It depends on your usage patterns.
If you access large files, or consectutive files, or keep reading from the same files over and over, then yes, you'll probably feel the benefits. LIkewise if you read from the disk the same time you write to it you'll probably experience a benefit.
I edit video and do all of the above. If you play games or do more normal work and have random hard drive access patterns then you may not notice as much of a boost.
Several friends say they love theirs. I have one, but only use it for backup (I do my editing on a RAID) so I haven't been able to put it though it's paces yet.
I think it's worth the $25, especitally for the afore mentioned 3 year warranty.