Pay-Per-Click Versus Blind Request Leads

I recently had a conversation with a friend in a different industry regarding online lead generation. Their two primary options were (1) Pay-Per-Click with the search engines and (2) industry-specific sites that encouraged buyers to solicit bids, which were in turn sent as "blind requests" to a handful of competing vendors.

Capterra is unique in that we offer our vendors both, but of course we only operate in the business software space. He asked me which method our vendors prefer, to which replied it depends on how Internet-savvy the vendor is. Those that are novices to online marketing prefer the RFIs, mainly because they are so tangible. But those that truly get online marketing prefer Pay-Per-Click for the following reasons:

1) PPC means the user is actively doing their own research, has read something about you specifically and clicked through to your website - where you control their experience and convert them to a lead.

2) You can respond more quickly to someone who submits their details over your own form than if they go through an intermediary.

3) PPC is less competitive. Lead gen services will send the lead to 3-8 vendors, typically. Whereas if someone contacts you, they may have also contacted 1 or 2 other vendors, but that's probably it.

Can anyone think of other reasons?