There is no doubt it adds warmth, depth and overall a much better sound quality than the phone microphone. It's easy to use and feels really well built. The only thing to keep in mind, it doesn't like loud sounds as much or doesn't deal with them as well as the standard mic. You get a bit of clipping and break up if you're trying to record something like a live band that is loud and your close to the source. The sound is far deeper, more forward and full sounding, but you are aware of some clipping and distortion once you're using it around with really loud volumes. For voice audio work, no doubt it's a massive improvement and highly recommended.
