I'm tempted to say it may depend on the chain/link combo...
Just fitted a SRAM link (dont know if it was a powerlink) to a 105 chain and like another contributor, i had to apply pressure to the cranks to get it to snap together. At this point you know its going to be a swine to undo....and it is
No amount of wiggling, applying pressure here or there will undo it. Not even special pliers. These need care sometimes BTW, ive has the rollers bounce out off the pins in the past when applying considerable force.
I seem to remember my previous link (not SRAM) was a swine at first, but then it got easier the more times i took it off. I'm hoping the same will happen with this one.