Roland SPD-SX Sampling Pad

Perfect sound quality, the best in the market. It is mostly suitable for live sets were the set is previously prepared, and allows to trigger a backing-track.
Very robust piece of equipement, I totally recommend the bundle with the Thon case + clamp, it's perfect for travelling.

On the down side, the interface is not very user friendly and the software for PC very limited. Also, the live loops options are not that easy to use and reliable, it's fun to use but not what you would expect for live performances and looping on the go.
Also, the built-in click cannot be used live or with a track, unless if you're setting the tempo for the song, meaning if you try to sync the click manually with a track, it eventually goes off tempo. There's an option to sync the click with midi, which I found it to be unreliable as well.
It would be cool to have a click sync feature like Traktor or other DJ-software does.