I use SM2, because that's what I play
While the multiple fire phases can make for very lengthy rounds, it does underline the danger that modern weapons pose, never mind futuristic ones. The down side is that unless you're very slick on combat, it means that those individuals who ony get to act once per round like melee people and teeps, can get quite bored. Especially if you have a PC maniac doing a spray burst attack on 5 separate targets with his machine gun. Twice.
Edit: Oh, except I don't know how to do an orientation roll. Generally those usually come down to is me rolling the dice and then deciding if allowing the mooks to act will kill, rather than challenge the PCs.