The most popular system in NATS is the 5-watch.. that's roughly - 2 mornings of about 7 hours followed by 2 afternoons of around 8 hours followed by two nights of about 9 hours followed by a sleep day and 3 days off. Because it's busier during the day and more staff are required, some staff will be rostered for day duties whilst their colleagues work the nights. So, for example, those guys might work 2 mornings, and 4 afternoons followed by 4 days off. Some cycles have a day off in the middle so at the end you get just 3 days off on the trot. There are variations to this pattern depending on local arrangements, but the basics are similar. There are no guarantees of weekends off but the watch system follows a regular 6-on, 4-off pattern so you can work out when you'll get a weekend off months or years in advance. If you become a shift worker, weekends mean nothing but it's a real joy to have days off during the week when the plebs are all working!
Annual leave for an experienced controller is about 6-weeks plus public holidays. This means that if you take a 6-day cycle as leave you get two weeks off (4 days before, 6 days leave, 4 days after). If you work your leave right you can get a lot of time off. It's obviously more difficult to get leave in the summer so local arrangements generally guarantee a certain amount of summer leave then you spread the rest of your time off around the year. In winter leave is usually easier to take on days of your choice.
I've met very few people who get as much time off as I used to - some of my neighbours thought I was unemployed. It's totally magic.