I've been on "alien war in London" several times and it really is the most realistic film attraction ever made. You run & sweat with colonial marines, people get snatched by aliens and quite real sence of thril land fear is generated. After I got used to it I scared some girl improvising a facehugger on her shoulder, grabbed my friend for a foot and provoked a reflexive slapp on my face... I've heard about (real) US marines picking a fight during attraction with (fake) colonial marines and people throwing up afterwards. Too bad it closed. I've heard the place flooded and insurance money was good and basicaly no need to reopen it, They should have open one in Japan.
On the other hand "Ride at the speed of fright" in San Francisco is cheeesy simulator ride (with even cheesier acting), but it does feature aliens style cinematography (in IMAX format) and sets.