I had a 45CT1 back in 77 and then later a 60CT2 and now a 60CT4. At first I went for the 60 because of the power (which you all know not much more) but I found out it's much less tiring carrying the 60 series because the flash unit is lighter although bigger. The extra power comes in handy only in term of faster recycling time as the flash still has significant charge left after each shot not so much in term of being able to shoot farther or with smaller aperture.