Two CDs and a box? I'll survive
I'm in Hong Kong now, and it's significantly cheaper and much faster by Steam. If I get it I know it'll be very much an impulse purchase, as there a lots of good reasons not to get back in the water. I just more vulnerable through Steam.
I guess I also feel generally comfortable with Sonalysts not leaving me "stuck" if Steam doesn't work out, and I half expect some of the freeware mods to be available, saving me some of the hassle and also making it more likely that other people will be playing with the same game.