I like the 3.3, but that is only because it is all I have had. Lots of power, easy to tune. If you send in your old traxxas motor they will send you a 3.3 for $130 plus $5 shipping.
I can't comment on either of those engines but i ran the OS .18TM in mine and it RIPPPED. I forget who i sold it too but he was super impressed with it as well. The OS is easy to tune and makes great power.