I'm just about to go with RBI over 4G and am confused about external antenna options.

I am 4.5km away from both a Spark and Vodafone 4G towers (They are both on the same hill). I have clear line of sight to the towers, I am at the top of one hill and they are at the top of another with a flat valley in between.

My neighbour (down hill) has RBI 4G through Vodafone and has one of these antenna: https://www.gowifi.co.nz/antennas-700-900-directional/ant-205.html and is happy with his 11Mbps speedtest, although I suspect this was over wi-fi and do not trust that it reflects the real speed of his connection. Saying that 11M is much better than the <1M I am getting through ADSL.

Antenna installation options seem to be: 

* Vodafone - One antenna by default $200 install,

* Spark - No antenna option through Spark, install and setup yourself. (Parts from go-wifi ~$300)

* Other providers offer installation options including dual antenna but so far seem to be expensive for what, to me, would be a straightforward install. I am confident that I can do the physical installation myself.

So, here is the confusion: Do I need dual antenna to get MIMO/better signal?

Unfortunately, the best place to install the antenna is on the roof at the front of the house and a dual antenna would have a very low Spouse Acceptance Factor.

I have seen this, http://www.powertec.co.nz/rfi-mimo-4g-lte-panel-antenna-700-2700mhz  that could be mounted high on a wall (the house is two storeys) and am wondering whether this would be a simpler (and prettier) solution.

The question is, would this integrated dual antenna work and give me good results? (or at least better than a single antenna)

Cheers, D.