Are you targeting 3 word keyphrases in your attempt to rank in G?

- The longer the tail (more words in the keyphrase) have better conversions that shorter phrases.

- The longer phrases are easier to rank for than shorter phrases in SEO

- The longer phrases that are exact phrases in PPC are also cheaper

So answer to your question, am I targeting 2 or 3. I am targeting 1 to whatever.

Aside from that, if the head (1 keyword) is sooo competitive, I target a bunch of long tails first until the site performs better and better then slowly works my way up going to the head.

I have used long tail keywords and converted well on some sites.

And used long tails on PPC and converted well on other sites.

But used both SEO and PPC on 1 site and strictly compare conversions where they are coming from, SEO or PPC, I haven't done that yet. So I think I cannot come up with a good answer to compare the two.

Although I have been successful in both, not all variables were the same to give a good comparison. I just know some of my sites are better for PPC and some are better for SEO. I target tons of long tail first if I can't get the head right away.

However, I'd elaborate to suggest that you not just target 3 word phrases. You should go after the entire sphere of phrases, because we never really know what folks are going to search on. That's the primary reason IMO why lots of content is a good idea. More chance to rank on some 3 or 4 word phrase that nobody thought of targetting. And the way to hit that of course, is lots of content. I believe that's one of the reasons blogs work so well - so much content.

you can gain links in a natural way

Think about tourism: city names etc.

It's true that the long tail (three,four or more keywords ) have the best ROI in PCC and in the natural organic results.