Hi Paul , I use a mifi Huawei , I find it quite good on the 3 network,my only regret is that it doesn't have an input port ,which I could add an aireal or booster ( not that I've needed one very often).
We have got an EE one only because the daughter works for them so we get it cheap and the contract is cheaper
but right now I am sat in the house Maxine is sat on the drive and my phone connects to the MiFi unit in preference over the home router that is is the same room as I am
it says it is getting a better quality signal from the 4G-MiFi over the 32Mbps home WiFi - - -work that one out
Directional aerials work much better the omnidirectional ones are a waste of time.
I use a cheap directional aerial like this with the Alfa router from Solwise, you can buy the router on eBay about 10 quid cheaper but no guaranty it will have the same chipset in it and will work with the aerials.