Yeah it's anyone's choice, but it shouldn't be that way. They say they get the same amount of work done in 4 days as they used to in 5. The business gets the same work out of them by paying 20% less. It's not fair on anyone. I think we need to stand our ground and demand the same compensation if our output is the same. Otherwise while you may feel satisfied with a 20% pay cut for an extra day, you'd be even more satisfied if you could just take that extra day. That's what everyone deserves, compensation for their work, not hours on the clock.
It's your choice, of course - but that kind of thinking would just keep the parent poster from getting the deal they obviously prefer.