Back when I was working with Dentists I worked closely with DemandForce and was considered a marketing partner. In fact I'm still at the top of their recommended consultants page:
Demandforce | Consulting Firms and they would also personally refer Dentists to me that had problems with Places. (Back in the Places days.)
I've blogged about DF some. Here's one post with some background.
DemandForce Responds to Google Places July Update: Dentists – See Google Review Templates you can Use - Google Places Optimization Blog
Anyway it's interesting because DF's core business and what you pay for IMO has nothing to do with reviews. The core service is recall and reactivation. Patient appt reminders and getting overdue patients back in the chair.
In order to do that it ties into the practice management software, auto emails patients about appts or when they are overdue for cleaning or whatever.
So patient reviews again IMO are just a free value-add service - in that you can set it up to also automatically email patients after their visit and ask them for a review.
Last I knew the service was about 300 a month with a guarantee that the service will more than double in recall/reactivation revenue, what you pay for it.
One the BIGGEST reasons DF Dentists rank so high though is not even the reviews.
DF didn't know this for a long time and I had to repeat it over and over to like 3 people before they even got it. But the way DF is set up, for every review DF gives the practice 1 1/2 - 2 citations. So back in the old days when citations still showed on the Place page a Dentist with 100 DF reviews would usually have 150 - 200 DF citations on the Place page. And back then IMO citations counted a lot more than reviews did. So I believe it was all the citations, more than the reviews, that boosted ranking.
With the blended algo I don't think # of citations counts as much and 3rd party reviews no longer show on the Google page.
But it's always the reviews that are in the limelight and that Dentists want when they consider working with DF. I always told Dentists they should not get DF just for the reviews because Google could change the game tomorrow. I advised them to make a good business decision based on the core service: recall/reactivation and if it made sense and would boost revenue, get it for that and think of reviews as icing on the cake. But in spite of that, most would get DF just to boost reviews.
I should mention I've also had demos of all the things the core software does and have a strong background in a variety of Dental technologies. The software is hot and what it does as a core service is worth the money.
But to get it purely for the review aspect, not sure that's wise. Well actually it depends on the market. In some markets like San Fran there is no way in heck you'll rank one page 1 or even page 2 without DF because most of the Dentists in SF have been using DF for years.
So those are a few of my thoughts about DF,
but disclaimer, I have not been very involved with them for awhile and things may have changed.