I have been running Samba on quite a few different builds for the purpose of watching video via Kodi on two different Firesticks with the latest being r44483 big on an RT N66u and r44483 giga on a WNDR4500.
The WNDR4500 is my AP and the RT is setup as a Repeater Bridge.
The only problem I have had is buffering if I try to watch video stored on the WNDR through the Firestick connected to the RB or try to watch video stored on the RB through the Firestick connected to the AP. The videos are not particularly large, normally just between 2 and 3GB and I have concluded (aka 'guessed/assumed') the problem is simply to do with the wireless link between the AP and RB as both Firesticks are wired (signal strengths are in the 90's with TX/RX rates at 450).
I do not get any buffering, even on larger files, if watching video from the AP on the Firestick connected to it or watching video from the RB on the Firestick connected to it. It is only when I throw a wireless link into the equation I have an issue.