Full disclosure: i work for Cel-Fi. I decided to reply your post because I was very interested to get your feedback on our new product - thanks for all your inputs.
About MicroCells: I think the main issue is more a stable Internet connection - our experience has been that Cel-Fi is very useful in cases where Internet cannot be installed reliably (ie not from Wi-Fi, or with low latency) in the places where you need most your cell phone. Many times, our clients are telling us that MicroCell was not a solution because of installation issues (think cabling, ISP) to get Internet in a specific place (this is mostly for our business customers). Of course, this comes from our customers - so there is a bias in our favor
Yes, Cel-Fi is expensive - we are the first ones to say it - but that's because we could not be happy with any other technology that produced unreliable boosters. We use very different technologies than any signal booster - Cel-Fi is made of a custom made multi-core ARM processor with lots of DSPs. The result is a very clean, clear and strong re-broadcasted signal from AT&T and T-Mobile.
I am really happy to hear your comments / critics about it - thanks for your posts!