One mile urban range would not be terribly useful for me. Especially when you have to buy two of these GoTenna units, over $300 total, to get that. I'd rather just walk that same mile in fifteen minutes. Or jog it in ten.
I would just buy a pair of GMRS radios. You can get a cheap pair of them for $50. Technically, you need an FCC license ($85 for five years) for GMRS. But during a disaster situation, would you actually be worried about that? Nobody is going to catch you making a brief unlicensed GMRS transmission during a disaster anyway. They would have to be out there hunting for you, with sophisticated equipment. Chances are, government priorities would be elsewhere during a disaster than trying to catch rogue GMRS users.
If you're really worried about being 100% legal for that short transmission during a disaster situation, stick to the FRS channels on your GMRS radios (GMRS radios allow you to use either low power FRS channels or the higher power GMRS frequencies). You don't need a license for the FRS channels. FRS is limited to 500mW output. But GMRS radios, on FRS channels, can go higher power - up to 5 watts (see link below for channels and max power allowable). I get about 1 mile range with my FRS radios in my suburban area (no tall buildings, giant hills or massive tree cover). The non-shared-FRS channels that GMRS radios can also use can go up to 50 watts. MUCH more power and range than those GoTennas. And a lot cheaper. I wonder if those GoTennas are going to require an FCC license? That would depend on the specific frequencies and power output. Even buying a license for your GMRS radios, two of those radios plus license would still be cheaper than a pair of GoTennas.
http://wiki.radioreference.com/index.php/FRS/GMRS_combined_channel_chart