I have been using an unlocked Huawei MiFi for several years now, in much of Europe. For the past two or so years, I have been using a 3 SIM (PAYG) in those countries where 3 have "free" roaming agreements. In those countries where 3 do not have "free" roaming agreements, I go to a phone shop, buy and local PAYG SIM (you need your Passport with you, in most countries, to do this). The MiFi allows for upto 8 connections at any one time. So, myself and my wife can have our smartphones on WiFi, as well as IPads and laptops, while in the van, or, indeed, while sitting upto a few metres away. This has worked brilliantly in Portugal, Germany, Spain, France, Belgium, Holland, Denmark and Sweden. The Huawei MiFi has a built-in battery, which gives several hours use between charges, and, can be charged from the Van 12v output, using a USB lead. It is clearly cheaper to use free WiFi in places like McDonalds, Tourist Information Offices, and even local Libraries, or campsites which offer free WiFi, but, if you want the convenience of being able to use the internet, from you van, on a campsite, Aire or even Wild Camping, This solution works just fine. The cost if you are using a "local" SIM is dependant on the country and network, but, in those countries where 3 offer free roaming you are either using your included data (if on contract), or, UK PAYG rates. The PAYG rates depend on what you buy, see the 3 website. Because I have had my current Huawei MiFi for several years, it supports only 3G, which I have found quite adequate, but, I do intend to upgrade to a newer model which will support 4G.
Hope that helps.
