Partly it is a matter of preference.
People from the Randstad (Utrecht, Rotterdam, Den Haag, Amsterdam) tend to pronounce it like a v or hybrid v/w, whereas others tend to pronounce it more or less like the English w (not the French w, which sounds like "oo-WA"). Quite a lot of people who pronounce the w like a v sound or v/w hybrid, often do not differentiate between v and f, s and z, g and ch. Be aware of that when you hear someone saying "Hij maakte een *kool", because he actually may mean to say "Hij maakte een goal" (he scored) instead of cooking a cabbage.
I have one pet peeve (hmm never used that term before..) And that is when people mix up s and z in their pronunciation. Just this week I was watching I can see your voice and carlo boszhardt (or however his name is written) kept doing that. Ugh I thought no not again! Why hasn't anyone ever told you.
Maybe I'll try that next time. I was stuck on a "Type what you hear question" because it says what I was doing wasn't in Dutch, I kept on changing things, soon the sentence was literally gibberish, (I had no more options, so I had better just type in some gibberish to let me lose a heart, because it wouldn't let me pass anyways) and it still wouldn't let me pass. It was pretty frustrating, thank goodness I found the "skip" button!