Hi Len,
Molotow definitely has a shelf life, but I'm not a huge fan of it for big chrome areas. It looks a little aluminum to me, and handles terrible. I love the pen for little touch ups on dash buttons and things like that, though. But I haven't found anything yet that beats Alclad. I know people say it doesn't handle well, and always want to clear it, but I just don't touch it. Sometimes it's inevitable while you're building, but I have been able to touch up those areas with my airbrush and you would never know it happened, because you can touch it up with such a fine paint flow that you can't even see it coming out.
I haven't tried Revell, but while it's shiny, every sample I've seen looks like it picks up every bit of dust in the room, and looks too thick. Also, I can't justify the cost. Looks like a lot of waste out of the can, but maybe it can be decanted.
I do have both some SPS and DSPIAE chrome I'm going to try someday. Maybe that will be better...
Hope whatever you try works out for you!
Art