I'll start off by saying that BOTH are (or should be) against the TOS and should be booted. I'll also say that G don't seem to be that bothered by them, and despite several complaints about one pure clicktrap, it's still there.
Maybe the difference between them is that MFA's may have at least a smidgeon of content. The click trap I refer to has one adlinks unit and three adblocks on one page - nothing else. Oh, and the back button was disabled.
Anyway, given that there seems only a small chance of Google booting you for having a pure clicktrap, is it a profitable business model?
My experience of being an adwords avertiser is not overly successful. I want people to visit the site, but it would also be nice if some of them clicked on the ads too. The reason they didn't, and I suspended the campaign for a while was content - I have shedloads of it. However, this time around my current campaign is very good at appearing above the other scammers - click price is enough to be at the top, but low daily budget.
So the business model for my new site:- A clicktrap as described above (no content - only way to exit is via an ad) and adwords. A couple of $ a day in adwords should be repaid by loads of clicks on the ads. Simple and foolproof!
Now all I need is suggestions for a topic.