Possibly one of the most important pieces of news circulating at the moment. The implications of this are immense:
1) The US did not extend the sort of deal Pakistan was asking for and now finds itself in a situation where it is looking rather powerless; there is nothing quite like refusing someone and then seeing them waltz down the street and get a far better deal...
2) China has shown itself to be increasingly assertive. They are not shying away from unilateral action anymore. And by the way, unilateral action on something like this nuke deal is very different from action on Taiwan, for example. The latter is a fundamental security interest. The former is China projecting global power unilaterally. I would say this deal signals China's coming of age from a strategic perspective. They have arrived.
3) Pakistan needs energy, energy, energy! Cheap, plentiful, safe... This deal is a huge contribution towards fulfilling the need.
4) Technology; the reactors are based on new designs and the level of cooperation with China has always been very extensive, no-holds-barred. Pakistan's engineers and specialists will have a lot to gain and a huge amount to learn from these undertakings.