O-1 is much more forgiving in the heat treat. Let me be a little more blunt. You can "get away" with more in the heat treat in O-1. Even with a less than perfect heat treat, you can still get good preformence. 1095 requires a very fast quench to get the best performance out of the steel. If you look at data from Admiral Steel it recomends you quench in water, which is what I used to do. Now I use an actual quenching oil that is formalated to take the heat out of the blade very rapidly. It's not cheap, $80.00 or so for 5 gal, but its performence is very close to water.
When I used water, I cracked alot of blades, with the new oil I think I have cracked one or two....