So far no issues with WIFI, but i use it in my house and the router is super close..... There was one time where the Wifi didnt work at all, and there was no signal. But i reset the Surface and it worked just fine.
I had issues with WiFi originally, but that was due to the crappy router that I was using. I had issues with that router with many devices and typically had to reboot it daily. Bought a new one and everything has been much better since. I do get some lag from time to time, but usually only when I'm pretty far from the router and pushing it. Overall the WiFi has been working pretty good.
I haven't had any issues with WiFi connectivity either but there is no speed difference between Wireless N 2.6Ghz and Wireless N 5Ghz, which is an issue.