I assume OP is talking about the issue that sometimes when the computer goes into sleep mode, when you wake it back up, the Wifi doesn't connect. And to fix it you have to turn Wifi off and then on again.
No issues here with my mid-2012 rMBP, Mavericks, and Netgear R6250 router.
I did, however, have what appears to be an identical issue with my Lenovo Thinkpad W530 and the Netgear R6250 (and an ASUS RT-AC66R). This was a known issue with Intel's Windows 'Centrino' wifi drivers for almost 18 months, and was finally fixed only a few weeks ago. Perhaps the new driver in Mavericks has a similar bug/issue.
[Edit: Oh wait... this affects only the 2013 models? Nevermind... 🙂]
I don't see such issue. I closed the lid every time when I am not using the my MBP. When I am back using it, it connect back to wifi almost instantly. I don't really see the issue other then VPN to my work will reconnect exactly every 5 min. No solution for that, but that is not wifi issue as far as I can tell.
I tried lower a beacon interval (50) on my router settings. It seems to be better but not definitive yet.
Talked to Apple, tried a couple of things on the phone. They did not acknowledge a known problem. They asked me to try another router and offered to replace the laptop if it was not a solution.
For some odd reason Apple seems to have had problems with Wi-Fi connectivity from time to time over the many years I've been buying laptops, iPads & iPhone's. It's almost as though they fail to take the issue seriously until consumers complain loud enough or return so many affected units that it costs Apple too much money. Why they fail to test and debug before shipping is quite revealing.