If you can, please give me your opinion on the following products. I haven't had the opportunity to try either one of them out, so I don't know how good they sound, or how the cheaper pedal compares to the more expensive one.

Thanks

Dunlop Rotovibe: http://www.samedaymusic.com/product--DAVJH4S

Hughes & Kettner Rotosphere http://www.zzounds.com/item--HUGROTOII