I asked this in the PC board but didn't get many responses, so I'll post it here. What do you guys think is a better ability for a light side guardian (planning on sneak attack damage)? Stasis field stuns longer and would cost less b/c of the light side alignment. On the other hand Force Wave damages enemies and pushes them away. Also one is a reflex save while one is a fortitude save. Does that make a difference? Do enemies typically have higher reflex or fortitude? Thanks in advance.
For sneak attack purposes, Stasis Field is much more effective.
A round is 3 seconds. Stasis Field lasts 12 seconds (ie 4 rounds) whereas Force Wave lasts 6 seconds (ie 2 rounds). That means you have 2 more rounds with Stasis in which to do sneak attacks. The damage from the Force Wave is insignificant compared to a sneak attack.
As for the saving throws, rogue-like characters and anything with high dexterity have good reflex saves. Fighter characters and anything with high constitution have good fortitude saves.
The preferable stunning power depends a great deal on your Attribute selection and Jedi class. if you are a Consular (which gives you the Force Focus bonus powers) with high Wisdom and Charisma, then Stasis Field is better for the reasons that Rabid Midget pointed out above. However, if you are not a Consular, you will probably find Force Wave far more reliable.
The Save checks are the primary difference. Almost every enemy in the game is built as a Soldier or a Guardian (which means they have excellent Fortitude Saves and weak Reflex Saves). The few enemies who are not Soldiers are Consulars (which means they have excellent Will Saves and weak Reflex Saves). Furthermore, all of the animals in the game have very high Fortitude Saves and poor Reflex Saves. This means that most opponents in the game are much more likely to Save against Stasis Field than Force Wave.
My recommendation is that since you are a Scoundrel/Guardian you are better served with Force Wave because enemies are much less likely to make a Save. Moreover, on occasion Force Wave can even scatter enemies just enough to set up a few extra Force Jumps for you.