My RBI connection is currently working with a single external antenna. The indicated signal strength is "pretty good" on B28:

Late night / early morning speedtest usually delivers 45 - 48 Mb/s down, which I gather is about right for a single antenna. But in the evenings it will be commonly be as slow as 10 Mb/s. I expect that if I installed a dual MIMO antennae that late night speed might approach 100 Mb/s.

My question is whether it would make any material difference to the evening performance, which seems to be controlled by tower congestion rather than the native connection quality.