I'm having issues with signal strength on an Archer MR600.
I've recently changed from a Huawei E5573 (portable Mifi device)
This shows full 4g signal strength and I was getting between 10 and 15 Mbps download and between 3 and 5 Mbps upload.
The MR600, positioned in exactly the same location sometimes shows 50% if I'm lucky, but mostly 25% or 0% signal with the same Three.co.uk SIM.
When I do get a signal, it's 3g only and speeds are rarely above 2Mbps down and 0.3 up.