compare to the UK
Pretty tame compared to the UK.
5Gb is a lot better than T-Mobiles 0.5Gb streaming allowance before switching down to browsing only - but neither cut you off completely. But at least both tell you what the limits are and T-Mobile are marginally honest when saying 'unlimited browsing'.
giffgaffs 'unlimited' may allow much more data use before cutting you off but they've recently confirmed there are conditions/limits, they're secret, extremely variable (as little as 2Gb has triggered it) and the normal uses are quietly being relabeled as abuse in the small print in the T&Cs. Can be a little difficult contacting an Internet only company to challenge disconnection after they cut the Internet as well...
Right now only 3 seem to still be really doing unlimited internet on phones. Good thing they don't have enough customers to saturate the network ;)