This case is neither a UCL case nor a class action, but I mention it because the concurring and dissenting opinion has a very interesting discussion of the "abuse of discretion" standard of review. Gaines v. Fidelity National Title Ins. Co., ___ Cal.App.4th ___ (Dec. 12, 2013) (Second Appellate District, Division Eight) (Rubin, J., concurring).
That discussion begins:
As appellate judges we are taught to consider each case in the context of the applicable standard of review which, for the most part, is one or more of substantial evidence, abuse of discretion, and de novo review. Many appellate decisions and some commentators have criticized the abuse of discretion standard as the most misused and most misunderstood of these. Our colleague in Division 6, Justice Gilbert, has said that the “abuse of discretion standard is itself much abused.” (Ziesmer v. Superior Court (2003) 107 Cal.App.4th 360, 363.) It is indeed.
Conc. opn. of Rubin, J., slip op. at 1.