All the Cool Cat pedals are in metal cases and are fairly rugged. The smaller pedals, like the Tuna Melt, are in plastic cases with very small plastic knobs that can break off easily if you're not careful.
The Transparent Overdrive isn't as transparent as I'd like it to be, it does color your sound slightly, but it doesn't give you that midrange boost that most overdrive pedals have. It also works well as a clean boost, with little or no distortion added.
The Tuna Melt pedal (and yes, it's named after a sandwich as are all the pedals in this series), has a nice swampy tremolo with depth and speed knobs plus a small switch to give a hard or soft sound.
Here's my YouTube review of the Transparent Overdrive.