MacBook Air external/portable battery options, recommendations? (Tekkeon, etc)

What's your favorite external battery? Given no modular MBA batt, figure this becomes pretty important for extended "away from wall power" time. (Outdoor enthusiasts especially.)

• http://www.quickertek.com/products/macbook_air_charger.php
• http://www.quickertek.com/products/apple_juicz.php
• http://www.batterygeek.net/MacBook-Laptop-Tablet-PC-Battery-Pack-s/1.htm (several product options)
• 3GJUICE MAC AIR external battery
• Tekkeon MP3750, MP3450 or MP3450i (MagSafe adapter available if you work at it, see this post.)

(Seeking good/best battery for my new, MacBook Air 13" 2010.)

More details: https://forums.macrumors.com/threads/1142397/

(Didn't get any response to above thread in separate sub-forum, cross-posting here, hope I'm not breaking any rules...)

Solar power

This solar-powered, portable power source looks rather interesting. Possibly used in place of (??) external battery or possibly to charge the external battery "offline."

• Brunton Solaris 26 Solar charger - 26 Watt (much cheaper on google.com/products listings below)
  • Google.com/products search
  • Amazon customer reviews