This has been a Mac issue for a long time, even before Mavericks.
Many Mavericks users report that their MacBooks take an irritatingly long time to reconnect to their local Wi-Fi network after waking from sleep. While this symptom had been occasionally reported prior to Mavericks, there has been a resurgence of complaints following the release of OS X 10.9. Something new seems to be at fault.
I am one of the users who have this symptom. In my case (13-inch MacBook Pro with Retina display), the length of the delay varies. Sometimes it’s just a few seconds longer than I would otherwise expect. At other times, it can take a few minutes before I’m back online.
When I initially check the Wi-Fi menu while waiting for a reconnect, no network names appear. After a while, my previously connected network—as well as any other nearby networks—eventually do show up. A successful reconnect typically occurs shortly thereafter.