Yes, SuperPACs and presidential races are another beast altogether. Like I said, I was talking about a general case, since you referred to legislators, which by definition excludes presidential candidates.
SuperPACs are difficult to play the devil's advocate for. They are a feature of running a widespread democratic campaign in a big country, where the ad impressions on voters are prohibitively expensive because of said voters purchasing power.
SuperPACs have very lax limits on contribution, but they need to be firewalled from the main campaign and cannot coordinate spending, and their power to target their spending is very limited. As far as I can tell, this firewall is as good as any such structure required by law and audited (e.g. finance, consulting, etc.). That is to say, it works okay, but not great.
Full disclosure, I am involved in campaigning professionally (not US) and was an independent OSCE observer of the 2012 presidential elections in the US when working for my country's parliament.
