I've been using a Vodafone 4G wifi dongle for a while. In Skye it was great, 60+ mb/s download. In Aberdeenshire it was less so, varying between 2 and 10. Now I'm in Inverness and live close to a school it's very variable, especially when the kids flood out and stream at 3.45pm. In my new flat, the signal is terrible, so I decided to go for full fibre at a similar price. I've never experienced any throttling, but this might be due to having unlimited download. If you want to go for 4G, I recommend you try and do some speed tests before you go for it, e.g. using speedtest.net. Beware though, as my giifgaff phone signal (O2) is always 5-10x the speed of the Vodafone signal I get here.