What is the catch? Do you just have to put in X number of hours on he clock, and the rest are yours with some flexibility during the work week? There has to be a catch... I worked for a firm that had milestones for billability and hours worked. Anything above and beyond was "banked time", meaning you got 1 hour vacation time for every hour worked extra. It worked out that I got zero paid vacation, and 10 paid holidays. Assuming 40hrs a week. It wasn't terrible if there was lots of work to bill OT was available, granted I didn't get paid OT either... Some people who where out of town working would rack up a weeks vacation in a week, and could take a lot of time off. I said F that place like a lot of people, and they have since changed their policy. THe attrition was like 20% a year. My current job is about 5% if that.
I have all the vacation I can use in a year now, and have flex time on a monthly/weekly basis. I could work 3 days a week if I want, but would need to be somewhat available to clients. Its stupid how much time I can take off, I usually run out of money and ambition to do stuff before vacation time.