Sounds like both of you are on Smarty SIMs, not direct Three?
You cannot necessarily compare the delivery characteristics of a vISP with a true one. On any internet connection. Mobile or landline.
It depends entirely on what the contract between them is.
My broadband basic info/help site - www.robertos.me.uk.
Domains, site and mail hosting - Tsohost
Connection - Three 4G, tbb tests normally 35-45Mpbs down, 65Mbps off-peak, 9-24 up.
If you never think of anything off the wall, you'll never think of anything original.