I've got a CZ 550 American in .270 Win., and love it. The set trigger on the 550 works like on the 527: you push it forward to set it. The unset pull is easy to adjust and can be adjusted for weight of pull, take-up, and overtravel. The "set" position can be adjusted for weight of pull only, and it it adjustable without removing the action from the stock.
Here is a link to the range report I wrote after I took it to the range for the first time:
https://www.24hourcampfire.com/ubbth...&topic=0&Search=true#Post1843857After adjustment, the trigger is so nice, even in the un-set position, that I don't use the set trigger in the field, unless I'm taking a long shot and have plenty of time. At 100yds, off the bench, I don't see any accuracy difference between shooting set or un-set. But it is nice to have the set trigger for long shots from field positions.