The test being done:
first of all, I bought a "light crossbow" to have as simple a damage range as possible, it had a 9-10 which made number easy to compare.
I unequipped any +x-y damage ring/amulets I had
I unequipped any increased attack speed I had
I bought some cheap jewelry form the ah that had both crit and crit damage and no other dps-relevant stats.
statwise, with/without the jewelry the relevant data are:
set 1 : 1.1 aps, 9-10 weapon damage, 1268 int, 17.5% crit chance for +50% damage, totaling to a paperdoll dps of 155.46
set 2: 1.1 aps, 9-10 weapon damage, 1268 int, 25.5% crit chance for + 136% damage, totaling to a paperdoll dps of 192.53.
all tests were against a single slow zombie in act 1 inferno, for the purpose of reliability on damage over time effects ( blizzard, venom hydra) I stood still and took the beating under crystal skin.
All results were consistent in increased damage with the higher crit chance/crit damage gear, all other things being equal ( no +%damage modifier of any kind, no followers)