We use Tooway at work as the work sites move around every few months. Ideal for instant broadband communications out in the sticks as long as you have power (and line of sight to the satelite). Saves waiting for BT to install a landline!
Pretty good connection speeds but as jruk says, the vpn kills it big time. Data usage wise, will depend how much you need, pretty sure Tooway have a variety of packages available.
Also if you go over your data allocation, can top up if required rather than upgrading the package. As far as i understand, in a similar way to mobile contracts you can upgrade to the next package up fairly easily but aren’t able to come back down very easily hence topping up can be useful.