Yes, I own it. I feel that 4.7 out of 3,000+ reviews is pretty good, and I would concur with most of the positive reviews.
That pump is listed at 450 L/min which is about 16 CFM this blower is listed at 70 CFM.
With the price of compressed air, the thing is easily worth the money. I think you can snag it a few bucks cheaper over on Newegg, plus no tax for my. I would still say that compressed air has the advantage in some tight crevices with stuck on dirt, but I was much more judicious with my use of compressed air, which probably allowed for some dust buildup. I use this thing way more often and stay on top of the dirt easier since I don't feel like I'm paying to use the compressed air.
It's handy for all sorts of cleaning jobs, not just Lego dusting, I blew out the bug zapper the other day.