Wow, might have reconsidered myself if I had read those reviews!
All I can say is hopefully it's just a build quality issue and you get a good batch cause I've not had any issues with mine. I was initially a little disappointed with the sound, but after use either it's improved or I've settled. As for volume, I've not got any complaints and as for the waterproofing, it lives in the bathroom windowsill which is in spray/splashing distance of the shower and is still going strong.