I just read A systematic review and meta-analysis on the therapeutic equivalence of statins. This artilce will not make any major U.S. headlines because it is a Taiwanese study from a not very well known journal. However, the methodology is sound and makes an important point to patients who need a statin and are deciding between a generic and more expensive brand name medication.
The study did a systematic review of all the studies which compared the different statins. They found that at comparable doses, statins are therapeutically equivalent in reducing LDL (or bad cholesterol). This would suggest that if statins are essentially equal, provided you use the right dose, then you should always go with a generic. However, the other thing they found was that "the only two statins that could reduce LDL-C more than 40% were rosuvastatin and atorvastatin at a daily dose of 20 mg or higher." In other words, those patients who need cholesterol lowering drugs and have to get their cholesterol down by less than 40% should be OK with generic, but those who need to get their LDL cholesterol by more than 40% should use either Crestor (rosuvastatin) or Lipitor (atorvastain). Though new guidelines should be out by the end of the year, current guidelines suggest that patients with increased risk for heart attack and stroke (all diabetics, mulitple risk factors,etc.), who are generally the patients we use statins in, need their LDL's under 100. This means that if you are at increased risk for heart attack and stroke, and your LDL is 160 or above, you should not take the generic (even if it is cheaper), but take the more expensive branded cholesterol medicines.
Fortunately, as I mentioned in a recent post Are Drug Reps and Free Samples Bad For Patients? It Depends, both companies offer coupons to offset the additional out of pocket costs, so you should not pay much more for Crestor or Lipitor than what you would pay for a generic medication.