The Classics have alnico V magnets, and the Probuckers have alnico II. I would then expect the Classics to be most prominent in the lows (and be fairly strong-sounding) and the Probuckers to be most prominent in the mids (and do a good job of cutting through the mix).
I do not have any guitars with these pickups; all I can say from personal experience is that my Epi SG came with the Classics, and they rocked my AC15 in a good way.
I must mention that I swapped the pickups, not because they weren't good, but because I bought the guitar in an attempt to make a poor man's Pete Townshend SG. At the time, there weren't any Epiphone SGs with stock P90s, so had to go with hum-sized P90s on a regular SG.
Guitars: 3 Fender Strats, Fender Jazzmaster, Squier Bullet, 2 Gibson Les Pauls, Gibson ES-339, Gibson Les Paul Jr. Special, Epiphone Les Paul, Epiphone Dot, Epiphone SG, PRS SE Custom 24, Ibanez AS73, Hamer Duotone, Larrivee D-03R, Takamine EG5013S, 1951 Epiphone Devon, Ibanez SR305 (bass)
Pedal Chain: BBE Green Screamer -> MXR Distortion III -> Boss CE-5 -> EH Stereo Pulsar -> Boss DD-20 -> BBE Boosta Grande