Only one I have used is the color I put on the M51 Super Sherman. Rather than try to find a close match in the Vallejo air range, or mix a couple of colors together, Lifecolor has the pre-'73 and post '73 Israeli colors.
First time using them myself, what can I say....they are OK, but I won't be trading in my Vallejo for them.
Airbrushing it on, it went down ok....rough 50/50 mix with their thinner resulted in a thinner than I would like mixture, so it took multiple coats to cover. Once it was on and dried, I found the paint to be on the rough side.
As far as brush painting....I can't really comment as I have only used it to just touch up a few spots on the airbrushed coat....so I don't know how well they would be to brush over a large area. I fear they would brush paint similar to Tamiya, do one pass and let it dry, no matter how thick or thin it goes on....as it skins over fast, and a 2nd or 3rd stroke will just pull the skin around, fouling up your surface. Probably not as bad as Tamiya will, but still seems that it leans in that direction. Again, I won't be trading my Vallejo in for them anytime soon.
So for me...other than a few colors that may be spot on for what you need (IE, the Israeli sand colors), I doubt I would buy too many of them based on my experience with this one.