Korg Sound on Sound is a compact multitrack recorder specifically made for musicians.
Pro Simplified use
Korg have attempted to keep things simple for the user, so selecting inputs is something the recorder does automatically, by scanning for a connection. For similar reasons, inserting a headphone jack disconnects the on‑board speaker, and there's an automatic input‑gain facility and a limiter, so you can maximise input levels.
Pro Built-in effects
The effects and processors are very usable, and are a definite asset: when you're trying to build an idea quickly, having to mess around with settings just to get something half‑decent can be a huge distraction, so being able to dial up a good cab emulation or a reasonably convincing tremolo preset is great.
Pro Unlimited overdubbing
What it does is provide a timing grid, and anything recorded is saved relative to the rest of the song's audio tracks, enabling the user to layer idea upon idea (hence the name) ready for mixing in your DAW later. At the same time, a mixed version of all the tracks is saved separately, making it quite possible to complete a mix in the box itself.
Pro Increase playback speed without affecting pitch
It's even possible to increase playback speed (without affecting pitch) to 150 percent and reduce it to just 25 — although overdubbing is only possible over slowed-down, rather than sped‑up, audio, presumably to avoid deterioration of quality when slowing it back down to normal speed.