A wifi shield you will recommend

Using Arduino Networking, Protocols, and Devices
5

Just found that all shields and breakout modules can be categorized by the chip:

  1. Microchip (many from China)
  2. GainSpan (GS1011 or earlier)
  3. Roving Networks (RN-171 or earlier)
  4. WIZnet (e.g. dfrobot)
  5. cannot figure out the chip on async_labs.

Apparently, GainSpan has great documentation in their website and it can support ad hoc wifi network.
Users please share your experience --
is ad hoc wifi supported by other chips?
(for GainSpan) if ad hoc wifi network is supported in Arduino's wifi libraries ?
if not, is it too wishful that it will be supported in near future?

-Frankie.