The one great thing I like about the capaC is the easy ability to create and use vWLANs.
The fact that they use the same radio leads me to the inevitable question how many vWLANs on a radio are optimal or practically speaking before the numbers start impeding the functionality of the parent wlan.
I have always, without reason, postulated that three wlans per radio (1WAN + 2 vWLANs) was probably the safest course of action.
What does THE ORACLE (bpwl) suggest or others of lessor wifi acumen think??
@anav, nice question…
According to the manual more than 30 will degrade the performance…https://help.mikrotik.com/docs/display/ROS/Wireless+Interface#WirelessInterface-VirtualAP
Personally i 've used at max more or less 4 virtual interfaces without noticing any problems..
Yes, very nice Question indeed…
I always assumed any number of vWLAN had performance degradation.
So for small Networks with the need of multiple Wireless-Networks,
I usually use the Access-List to assign them to the Network
For exemple:
Guest : VLAN100 via default TAG (wireless interface)
Camera = VLAN200 via Access-List
Home-Network = VLAN300 via Access-List
Nice graph!!!
So one has to take into account interference from neighbouring APs on that channel as well.
I note in the clean environment, degradation is slim, up to 10 SSIDs (vWLANs) and only 5% degradation.
However take a realistic view of 3 Aps on any one channel in ones area then THREE SSIDs (1 wlan and 2 vWLANS) keeps things at or under 5%.
Be aware of SSID (AP) with b-rate still enabled. (using 1Mbps for beacons by default)
https://waitbutwifi.com/lowest-basic-rate-vs-number-of-ssids/
(Andrew von Nagy 's ssid-overhead-calculator is still off-line)
See you can get over 10 without any problem ? 
In my test I did disable B, only G/N.
Yes, it seems neighbor interference is more important than the number of SSIDs per AP in terms of performance.