I'm two nights down with my sleep buds, but so far they're pretty good.
My main concern is that the included sounds are all very "bright" - there's a lot of high-frequency sounds and very little, to no bass.
I love camping near the ocean, and one of my favourite things is going to sleep with the sound of the waves crashing. I'm sure if I was sleeping right on the beach (I'm not) there would be a lot of higher frequency noise from the waves, but staying a few hundred meters inland, behind tall sand dunes, you are left with the gentle, bassy thump of the waves and very little of the high-frequency white noise type sounds from the breaking water.
Is it just the design of the drivers in these devices that they can't emit much bass, or is it that the sound library has been tuned all towards high frequency sounds - rain falling, bright streams burbling, even the crackle of a campfire.
All these sounds seem like they're recorded right up against the source - I don't sleep right next to a campfire. I don't sleep right on the beach, and I don't sleep with my feet in a stream. I sleep further away where the high frequencies are attenuated more by distance, leaving more of the softer, gentler and darker low frequency sounds to soothe me while I drift off to sleep.
I would really appreciate some soundscapes added to the library with more emphasis on the low end of the sound. I don't need bass that rattles my teeth, but I do want a more fuller and richer soundscape.