Yesterday I received two shiny ESP-201. I ran some tests to figure out the improvement of sensitivity when using the external antenna. IMHO it is quite impressive, not gonna use those on-board antennas anymore if I have the choice;-). I also found a way to put them on a tiny breadboard, mere brut force actually...
You'll finde the whole review here:
http://blog.squix.ch/2015/02/esp8266-esp-201-breakout-board-review.html
Cheers,
Dani