Star Trek Online? You don't have to play the beta for STO to get an idea of what it is like. Play Champions Online and you will get a taste. STO is simply CO with a new character mesh and modified UI.
But MWLL beta is built off Crysis, so some bugs will be easier to handle.
Hell, Champions is 10 times the game STO is (at least when comparing game now vs. Champions beta). Horrible game that only has the name to help it sell.
I know that MWLL is based off Crysis (OK game) but just don't want to have another bad beta experience that ruins me for the final thing. Once the release a few versions of it and fix bugs I will try it.
The only beta I want to play now is BF BC2. Can't wait for it on PC, as the PS3 beta was great (minus the control issues with consoles).