The best panels are any you can afford. I know you are refering to the claims of some panels that they get more efficient in low light conditions, in reality the increase is negligable at best, I have a year of logged data from 2 solar arrays, one is 2Kw of First solar FS-50 CdTe Thin films (which clain a 10% increase in efficiency @ 400W/M Vs 1000W/M) And 1710 Watts of Evergreen 190s. There is no real difference percentage wise between the 2 arrays in any given sun conditions. One array goes through a MX-60, the other goes through a FM-80, all the same setpoints.
The Thinfilms are 48V nominal, 20 panels in parallel, the evergreens are 3 series, 3 parallel for 54 volts nominal, so it is pretty much a apples to apples comparison.
Dustin