Sip:
I'm with you. I've had those top of page rankings. At some points they are PAC listings with a pin, and then there could be other organic rankings and then below it, the pac.
My simple experience is that the higher on the page the more traffic the site gets. So I like them. On top of that, whether within the PAC or not, I get higher rankings, and customers that become buyers do tell us they read reviews.
If people are in a buying mode, they'll work their way around your site, different available information and to review sites. If they like what they see they'll buy.
We get more traffic when we sit on top of the page. We have gotten the most traffic when we had situations with a #1ppc ad, one or more organic and/or organic/pac rankings on the top. The benefits are huge.
To check on that, we've been able to use ppc campaigns that tell us how many impressions there are for certain phrases, and then we can total up our clicks. We can direct count the ppc ones. We add the organic for those phrases (when people aren't signed into gmail, and we create a formula to spread out the (not provideds) to all the organic traffic.
How to get there??? SEO JUICE. Its on page and its outside links, at least in my experience.
There are other factors in my experience. What I've seen over the past several months for some sites whose visibility floated between above the PAC with strong organic rankings or #1 in the PAC via a blended result of Local and organic strength...is that google seemingly has floated these types of sites back and forth a bit.
I just looked at one of those smb's using two different terms for its service with city name (city name first)
city name/(service described one way) and city name/(service described a second way)
This particular smb has had a strong ranking for its service/city for years.
In one variation it was at the top of the PAC. For the other variation it was above the pac, as one of two sites. The other was a well known directory and it sat above the directory, and then below those two organic sites was the pac.
In the case where it was at #1 in the pac on google.com it also sat at #1 using the classic version of google maps. In the other case where it was in a separate organic ranking above everything else it was ranked #11 in classic google maps.
The business is a type with multiple vendors in every city. (this was a search for a major city location). Generally the businesses in this industry don't have killer killer link profiles. This one does. It has links from strong pages that generally businesses don't get. It used one of the variations on a strong link effort that has been published in the past. I've used that also when I can in situations where I can get similarly strong links.
I should probably go back and do an exhaustive study on the smb, looking at many factors, including on page seo, deep link research and comparative citation sources to give a full report.
In sum though I can tell you the business is getting a lot of traffic and has been for years as its position in google.com is always strong regardless of whether in the pac or above the pac or both.