To me, this says you should enable it if you care more about 2.4 GHz wifi performance than USB 3 throughput. If you value USB 3 throughput more than 2.4 GHz wifi performance, leave it disabled.
It will also depend on the quality of the shielding of the device you plug in (including its USB cable). A poorly shielded cable or disk can still generate interference, in which case IMHO you should replace either of them.
When will appear in firmware ? The LACP for teaming LAN ports
When Asus decides to add this. Which means probably never in the RT-AC87U case, since it only has three Ethernet ports on the Broadcom switch.
In any case, I always recommend people go with a managed switch if they need link aggregation rather than relying on their router.
I upload 384.4 on my AC88U and works in general fine only have problem to see movie on my Samsung TV from USB drive connected on router. After 58 seconds movie stop. After movie start can observe bad image time to time until stop. With 384.3 movie work for longer time but show same problems with image. I go back to 380.69 where work perfect.
DLNA support has always been quirky, it's nothing new. Personally I recommend people move to a dedicated solution for this if their clients are having issues with minidlna. Supporting every buggy client out there is next to impossible for a minor project such as minidlna.
Am i rite in thinking QoS is closed source so the meters being wrong way round something that needs reporting to asus?
Everything tied to the TrendMicro engine is closed source.
You'll have to first reproduce the issue using the latest stock firmware before reporting it to them. Use router_feedback <at> asus <dot> com for reporting.
Note that if you are using a VPN tunnel, then this is known behaviour. At this time there is no solution to this.
Any way to disable spanning tree on the repeaters? The menu for switch is not there when the device is in repeater mode.
Simplest way is to temporarily switch to router mode, disable it, then switch back to repeater mode.
There's an nvram you could manually set over SSH but I don't remember it off-hand, sorry.