What is the test for preferability in a class action?

The preferability analysis was neatly summarized by Perell J. in De Wolf v. Bell ExpressVu Inc. (2008), 58 C.P.C. (6th) 110, [2008] O.J. No. 592 at paras. 47 - 50: For a class proceeding to be the preferable procedure for the resolution of the claims of a given class, it must represent a fair, efficient, and manageable procedure that is preferable to any alternative method of resolving the claims … The preferable procedure criterion requires an analysis of whether a class proceeding is preferable because it constitutes a fair, efficient, and manageable way of determining the common issues presented by the claims of the proposed class members and whether such determination of the common issues advance the proceeding in accordance with the policy objectives of access to justice, judicial economy, and the modification of the behaviour of wrongdoers…. Preferability captures the ideas of whether a class proceeding would be an appropriate method of advancing the claim and whether it would be better than other methods such as joinder, test cases, consolidation, and any other means of resolving the dispute …. In considering the preferable procedure criterion, the court should consider: the nature of the proposed common issue(s); the individual issues which would remain after determination of the common issue(s); the factors listed in s. 6 of the Act; the complexity and manageability of the proposed action as a whole; alternative procedures for dealing with the claims asserted; the extent to which certification furthers the objectives underlying the Act; and the rights of the plaintiff(s) and defendant(s) … [references omitted].