I just received mine yesterday. I notice my a2 had little problem (wifi connection disconnect & very slow speed) to connect with 5ghz wifi from 2nd floor (router at 1st floor). Comparing speed test with my old rn3, rn3 speed much faster by large margin. If u do speed test in front of router, then mi a2 can get full speed.

One more thing, speed with my 4g connection also not as fast as rn3. Really wierd. U guys experience the same problem?