Learn 6th ed or go directly to 7th ed?

[Metzik]

Hi guys!
I bought CoC a while back, never used it, hoping someone would GM the four small stories that come with the package.
I'm thinking of doing it myself, so the question is: would it be easier to stick with 6th edition or go for 7th edition? Since 7th edition obviously hasn't reached FG II, which books should I buy for 7th ed?
I ask since Treegreen made the extension and 7th ed might be easier to wrap your head around.

[damned]

Many people still use older versions of just about every ruleset. Some out of rules preference but many ore out of a desire not to buy new books all the time.
id probably stick with 6 because the books for 6 are included (its a commercial ruleset) with the ruleset.