I have 4G data on my BlackBerry Z30.. Most I can get from it is 2-4MB Down..
When I share the connection via Mobile HotSpot I can get up to 6-8MB Down..
Speed test on BlackBerry Z30
Speed test on my Note 4
I've put data on my Note 4 and shared it and it's the same results..
I've used LIME and Digicel Data, Same results..