Pirogoeth is right, a lot of people that bash BH techniques probably have never used them and are going off of what other people are saying. I spend a lot less time building high PR and relevant backlinks using BH than i would WH. Either way, if your not on page one for your niche your probably in the wrong biz regardless of how you get your backlinks. BH RULES!
Neither! Link exchanges carry little weight now with the major search engines. Get yourself some good one-way links in, write articles etc.
One way to get around this problem is, when someone links to your site/page with an unoptimised backlink, send them a polite email and ask if they'd like to link to you with a specific anchor. You'd be surprised how many people will accommodate your request.
Mix it up. Request link exchanges, manually comment on blogs, blast abandoned blogs with Scrapebox (greyhat), write articles, etc.
Many of them are talking about black hat seo, how many of them have actually used it? Don't repeat the words of seo scammers. Directory submission, article submission....do you call it natural? Read the Google TOS. Anyway you should be more concerned about the content. You can use black hat seo tools but you should know your limits (big question how do you know what is your limit?).....as all the respected members have mentioned go for a "natural link building". You will never have a fear of Google ban.