The majority of these tactics are outdated link building methods that will only get your site penalized or do nothing while wasting your money. After Panda, article marketing sites are dead. Blog and forum comments are typically nofollow so they will do little for your rankings. PR (I'm assuming your talking about press releases) can be done easy enough on your own through sites like PR Web, but they are not always that effective in gaining links unless you have a catchy release that others will want to write about. Directories are useful if you choose the right ones. I rarely use more than a few high quality/respected directories. So to answer your questions here I go:
1) Of the other methods (other thank custom link acquisition), how would you rank their effectiveness?
Outreach (I can't endorse paid links though) and quality directories would be the best methods mentioned. Like I said, there are only a handful of directories I would recommend and you'll probably get the complete opposite with a company promoting this option (meaning you'll be added to hundreds of spam directories that may penalize your site).
2) The other methods seem kinda gimmicky, is it worth the time/money? Most of the options you mentioned are gimmicky and a waste of money. You should instead focus on guest posting, outreach, and other methods that take hard work but produce more results.
3) Have you seen sites rank well for competitve keywords using articles/bookmarking/blog comments/directories etc?
I have seen sites rank well that have these, but there are typically a number of other factors earning them those ranks.
4) How do you know i a company is going to them manually as they claim? as opposed to using some automated software. This would have to be judged on a case by case basis from talking with the company. See if they'll share some of their other work, testimonials, results, etc.