We've done memberships as well.
Your experience might differ, but we have found it more problems than it was worth.
We use a strict set of particular types of links to each client / website. Some include creative 'gems' like the ones Wheel has created / develops. This consists of about 5% total of any profile.
The rest are a careful mix of a range of sites.
Remember that in each niche only a particular number of unique c class links of quality is required to take position one.
People laugh at business profiles, local niche directories and citation links on a National campaign.
But mixed in with associations, memberships, proof of business links and "gems", the value of those links is magnified in my opinion.