I haven't but there seems to be some false advertising on their 9v batteries (same price), I'd be wary.
http://taperssection.com/index.php?topic=154512.0
Thanks. I've run across a number of "if it seems too good to be true, it probably is" scenarios today. I guess this might be another example (and I'm not willing to be the guinea pig to test it out so I'll just let this one pass).