While this most certainly doesn't sound as good as a full-sized, professionally crafted didgeridoo, it still sounds great, especially for $70 (price at time of writing). Compare to most professionally crafted wooden didgeridoos, which can easily run you more than $500, sometimes closer to $700 or $800. The sound quality is probably due to the curved shape of the interior space giving some nicer acoustic qualities than a straight tube would. Further, it looks beautiful with a very high-gloss finish on the outside, and I personally love the lighter natural wood color.
There are a few interesting things about this that you can't do on a normal didgeridoo. For one, since the bell (opening at the opposite end from the mouthpiece) is so close to you, you can put your hand over it to mute it, which also drops the note a bit. Since the bell isn't completely open--look at the picture, there's some didgeridoo in front of it--some of the sound bounces back at you. Coupled with how close the bell is to your head when you play, you can hear yourself quite well on this.
As for the spiral didgeridoo as a didgeridoo: the mouthpiece is just large enough that I can play almost a drop octave note--this is where you make your lips looser and they vibrate at a lower frequency than the drone, producing a very deep (but often raspy) sound. The backpressure is a bit lower than I personally like (I prefer instruments with quite high backpressure), but it's still at a very good level for playing. It's easy to circular breathe and play for a long time on one breath, though I don't know if I would recommend learning to circular breathe on this. Overall, it's a pretty easy instrument to play for someone with a little bit of experience under their belt. I don't know if I would recommend this for someone looking to learn how to play--it's probably perfectly fine for that, but I might recommend a more traditionally shaped instrument with higher backpressure if you're just interested in learning how to play (for learning to play, higher backpressure is generally better than lower). The vocal response is quite good in all registers from low (like growling) to high (like dingo calls/shrieking). Finally, the size is small enough to easily fit into most backpacks or even 17" laptop bags if you're in a pinch and need a makeshift carrying case. Really anything
In conclusion: it sounds great (especially for the price!), looks great, lets you do some interesting things with the bell that you can't do on a straight didgeridoo, is easy to play, and very easy to carry around. At the price, this is absolutely worth it for any didgeridoo players thinking of getting one, especially if you need a good-sounding and highly portable instrument.