F-16 beats JF17 in agility, range and max payload.
Agility cannot be so bluntly awarded to F-16 vs. JF-17, but yes in range and payload F-16 is winner, again when flying with full load F-16 looses its agility vs. JF-17 with full load.
JF-17 have IFR, which older F-16 have not, hence the range is circumvented.
JF-17 turn around time is shorter than F-16, hence more payload edge is circumvented too.
JF-17 can be overhauled far quickly and cheaply than F-16, giving more operational readiness.
JF-17 have no operational limitations or monitoring by third parties, which unfortunately is always the case with F-16.
JF-17 in present state is far modern and advance, in avionics and weapon integration, than any F-16 of older than blk 52.
JF-17 have array of weopans integrated with it, which makes it true multirole and force multiplier.
JF-17 can be a game changer for any airforce of the world, which older F-16 can never be.
JF-17 have more potential to grow than F-16, soon JF-17 will be having AESA, which will give it an edge above any F-16 Pakistan have in its inventory.
Pilots are more comfortable flying JF-17 as compare F-16, which makes a huge difference in maneuvering, which world has any way seen during the airshows.
At the same time Pakistan has mastered the skills of flying F-16, we also know its strengths and weaknesses, we have infrstructure, support services, which we like to exploit to max. and with more F-16 it's operation gets cheaper. Its not only the performance reasons, which compels PAF to continue with F-16, for the time being and there's a bit of nostalgia involved too.