The problem with your suggestion is that there is no general car rental forum - only those for individual companies.

No, that's what the Other thread in the rental car section is for.

In my opinion, posting there is to your benefit, instead of in this section. Obviously it's your call. But I'm almost certain there will be more answers, more analysis and discussion, and the answers will likely be different than the "choose the cheapest" or "Priceline it" seemingly common here.