I don't have a particular brand that I use, actually; it's usually whatever is on sale or whatever comes in the colour that I need at the time. I've been using the bucket-style from Lepage most recently because I've needed a big quantity all at once, and it's pretty good. It's dryer to the touch than a lot of other brands, which I like, but it's really up to personal preference. I have also used Elmer's in the past (in the tube), and it's also decent quality.
As far as I know, it doesn't dissolve insulation foam. I'm not sure what it is that you plan to use it for, mind you, but I also don't think you'll be wanting to use wood-filler on foam in the first place. It only sticks really well too wood and wood-like products, in my experience. If you're looking to fill cracks/make a smoother surface, try something like Gesso - it's like thick acrylic paint, and can be slapped on and sanded in a similar way to wood filler, but also works on foam.
If you have any other questions, feel free to shoot me a note, and I'll try to respond as soon as I can.