I currently own two JuiceBoxes, and I am not trying to make excuses for anyone, but fwiw, my experiences with technical support from this company has been stellar.
Unfortunately, like all small startup organizations, they tend to be spread too thin. They probably are getting a flood of emails daily, so I am certain it must be quite challenging to keep up with frequent requests for customer support. I have written them a couple dozen emails over the past several months; all but one promptly answered. That is a fairly decent track record. Thus, I have been successful in getting my fair share of technical support, both in terms of H/W and S/W issues with my JBs, via regular emails.
I have never needed to call eMW on the phone (although I have their number). However, I have the advantage of living about 25 miles from their location in the SF Bay Area. Since my first JB last Summer, I've been their a few times (including weekends) out of general curiosity to keep tabs on new product developments, as well as for direct "hands-on" technical support. Most businesses would not be overly receptive to customer visits to a production facility, but I had no problem just "dropping in".
Most recently, I had some fairly troublesome WiFi issues with both of my JuiceBoxes, for which Matt and Valery himself were extremely hospitable and helpful to resolve for me. Matt even made a "house call" one evening at absolutely no expense to me, to more fully understand the explicit nature of my home networking problem and made sure both "the fix" worked to my complete satisfaction.
I will not give out their business phone number (publicly), since I know they prefer customer contact via email, but their number is clearly shown on any eMW packing slip that ships with the product.