I haven't run or played this game yet, let alone via VTT, but when I do I will use MapTool via rptools.net (I just mentioned this program in the maps thread). It is a combination mapping tool and VTT. It is free. My gaming group uses it to play D&D. We started with Roll20 but after the data breach (https://blog.roll20.net/post/1869631243 ... estigation
) and the general limitations of Roll 20 including paid features, issues with voice chat, saving maps, and map size, I switched to running with MapTool and haven't looked back.
I would not say MapTool is a solution that doesn't require some learning. However there are good videos explaining features, a wiki, and an active user community. I was skeptical at first but after spending time with the program I am amazed at all the things it can do. The developers are working on many improvements of late and have just added the ability to play sounds for the players via the program, which would be a nice thing for an ALIEN game. Such features require a small bit of coding (3 lines or so) but once you have it written once you can use it as boilerplate. I grabbed code someone had posted online to use for sound in my games.
You can also create rule sets (they call them 'frameworks') for games. I haven't seen one for ALIEN but I would feel comfortable adding most of what I would want myself. I can think of many ways in which MapTool would be an excellent way to run ALIEN. For example the ability to add a map to the program from an image or PDF (such as from a cinematic adventure) and to reveal it or conceal it zone by zone with vision blocking as the player characters progressed through it.
It's not the prettiest user interface or mapping tool. For the price (free) and the feature set, it more than gets the job done. You also don't need an account or to provide personal information to use it. Every player just needs to have the program installed and you can run the game using your PC as the server.