A 12" give you aproxamatly 2 times the light gathering caperbility of the 10" and a theoretical magnitude limit of 13th mag,a 10" gives a theoretical mag of 12.8 but while that might not seem very much it is infact quite significant when looking for faint objects, so if as you say weight or dollars are no problem for you, go for the 12" you wont be sorry. astroron