DNA Finland: Range of 3.5 GHz Massive MIMO = 1.8 GHz Traditional
Adding more antennas makes adding cells unnecessary. I don't have cost details, but the innovative Finnish telco, DNA, suggestion of using Massive MIMO in the 3.5 GHz spectrum could be very interesting.
Pal Zarandy, of the extremely informative site rewheel.fi, writes "DNA, one of the Finnish operators publicly shared their plans about using 3.5GHz with 5G massive MIMO, deployed on the existing 1800MHz macro site grid (i.e. no site densification needed, no Capex hikes), to push home broadband primarily in the outskirts of bigger cities, lower pop areas."
This is consistent with what I heard from Softbank Japan, the first with a large deployment of Massive MIMO. Softbank told me they tuned for better performance at the cell edge rather than greater total speeds. Beamforming/Beamshaping gives the operator many ways to focus the signal as desired.