Ure wrong. Read more on i5 spec. They could have made it more stringent. So he might have a point. On router settings etc and isp. Especially DNS set it at ure isp dns. Not google etc.

for ya info.

As it is i5 best is

Wifi

802.11n 20mhz Width (Enable Shortguard Interval)  on 2.4ghz 1-11 only ( so wont work on 12,13 and ppl who use 40mhz width/auto on 11. The prob is most routers use shortguard interval option only with width either at auto or 40mhz. So no choice to enable it. Difference aint much just 8Mbps difference. aka 64 vs 72Mbps. So do it at ure diescretion Also at 40mhz u will get full 270 and with SI u get 300Mbps. 20 is 130 with si at 150.

802.11n 40mhz Width (Disable Shortguard Interval) on 5ghz at Channel 40.

this is what i am configured at and its working perfectly hand to hand with all my idevices at home which the full list is
ipad, ipad 2, ipad 4, iphone 4, iphone 4s, iphone 5

From what i saw on the FCC spec on the wifi power transmit. The higher channels transmit more on the router side but requires less on the ideviece. But from anandtech 36 was the best dbm. So set at 40 with Width 40mhz which is supported at 5ghz.

3gs wont work cause i change to 11n only on 2.4ghz. 3gs gets the update via itunes.