I've done a little research sorting out the basic features for comparison, SEER, HSPF, noise ratings, etc.
The thing I'm not quite sure about is the difference between the scroll compressors and the traditional piston compressors. Why would you choose one over the other? Seems like the higher end models that use the R-410A refrigerant use scroll compressors. Is there enough time on these things to asses their reliability over time?