I have 4 generations of clones: Gen1, Gen2, Gen3, and Special Generation(SpecGen).
The Gen1 clones are the first to come and very few are left and here are the reasons:
upon suffering severe damage their cell structure breaks down and the clones literally melt into a clear puddle.
This Generation has more dumb than smart. 20 out of 2000 of these exibit sentience and personality. the "Dumb" clones act monotonous and only follow orders. The "Smart" Gen1s were able to be rehabilitated into citizens when their service was over.

Differences all Gens1-3 clones feature from PD is the ahoge(cowlick) is different than PD's. Gen1 clone's eyes lack a pupil. Gen2 Clones (to be drawn soon) are slightly taller and exibit telekinetic powers. Gen3 clones have fewer distinctions however they all have different personalities leaving Gens 1-2 as more reliable as military use clones as the grand majority save a hand full choose to enlist.

The Gen1 clones are always dressed in a dark gray full body jumpsuit and are given either heavy or light armor (above in the pic with helmets). Rehabilitated clones all choose to wear the civilian (far right) clothes a certain way (ex: single stripe + sleeve means this clone served as infantry) and over their jumpsuit. All Gen1 clones have a taste for vanilla pudding and often seen eating from a cup of pudding on many occasions.