well it really all depends... The feria story is true, if you use it and then thry to go with another color line, it can/will cause extreme damage to your hair. Metallic dyes dont mix with other haircolors at all, but feria does produce a very pretty and multi dimensional color, you just have to ask yourself if its worth risking your hair. I have no experience with natural match, but I can tell you that if there is already color in your hair, color wont lift color. So if your hair already has color on it, dont expect it to appear lighter most likely what will happen is your color will come out uneven because of the previous color(s) in your hair strand. Its kind of technical, but depending on how much lift your going for, or even if you just want to go darker, what they dont tell you on the box is the level of developer is most likely the same for all of the color applications, and that causes more damage to your hair (using higher chemicals than you need). My advice to you would be to go over to your local beauty supply store (sallys?) and ask someone to help you pick what you need. It should cost close to the same, if not less than whats in the store, and do less damage.
Sorry for the run on advice, hope that helps, I have tons more info if you need it!