ESP8266 serial-wifi: antenna options
I've been playing with ESP01 and ESP03 and the ceramic antenna beats the PCB antenna by far.
While doing throughput tests I could not get the ESP01 to reliably get more than 1mbps until I touched the antenna with my hand (getting 10mbps). With the same program on the ESP03 the rate was always 10mbps. 

Also with ESP01 I get 20-90ms of RTT in my home WLAN and with ESP03 I get a steady 2-3ms.