When I had 5 weeks ago I never took all of it. The environment didn't support it. It was very much the "here are 5 weeks of vacation we hope you won't use".
Now I can a week or two here and there, a few days off, a long weekend, etc. It's my job to plan it out, balance my work, and go. Thinking back on last year (without going over my calendar) I'd estimate I took between 5 and 6 weeks of total time off.
I think the key point you make is that it depends more on the culture/environment than the policy. You can have a 5 week entitlement and still feel pressure not to take it. Or you might be able to take more than 5 weeks by going into "vacation debt" if your manager approves.
There's one distinction though: at least with a minimum entitlement you'll be compensated for unused vacation. (At least that's how it worked at a previous employer of mine.. it might even be the law?) So even if you feel pressure not to take it you'll get a nice payout. Not the case with "unlimited" vacation where nothing's on the books.
Now I can a week or two here and there, a few days off, a long weekend, etc. It's my job to plan it out, balance my work, and go. Thinking back on last year (without going over my calendar) I'd estimate I took between 5 and 6 weeks of total time off.