I have the new version of this, and it is absolutely fantastic. We recently moved into a new area, that is 4 miles away from the nearest exchange so home broadband (ADSL) is a nightmare, with speeds of under 0.75MB at it's best. There is no cable in our area either, so Virgin isn't an option.
I turned my attention to mobile broadband. I tried a 3 sim in my iPhone 4, and ran a speed test - at home I was getting about 3MB! Result!
So, I went for it, and bought the MIFI 15GB at £20 per month on an 18 month contract. I'm glad I did. I average about 4.5MB at home with this and between 2-3MB in and around Glasgow, where I use my iPad.
I couldn't be happier with it. Home and mobile broadband for £20 a month is a good deal to me.