It depends. When I am not in a hurry or don't need big sums that's the LocalBitcoin. But It's quite a rare case as professional exchangers offer a really seamless experience with a tom of customization that comes in handy for trading. And when you want to invest a decent sum of money it's superb as well. Here's a good example btcbit.net/buy-bitcoin-btc-with-credit-card
Wow. That's super helpful. I've been using this exchanger for several days. And what can I say? It's pretty good I will recommend it to all my friends now.