I really like Colorbox. I had a Brilliance one and it dried up quickly. Now that could have just been that one pad, I don't know. But since I was so happy with my Colorbox chalk inks, I just stuck with them.
My vote is 1) Pebbles, in every color kit and 2) Versamagic chalk ink. Both provide different looks/effects. I use Pebbles to ink over MM paint and then can put MS glitter over the chalk and it still shows through!
I think it falls in here, I bought the Pebbles Inc chalk and when I went to use it on stencils I notice sometimes near where the stencil starts its darker.. I watched a tutorial and it said to start on the outside which I did but I dont get why there is more chalk on the edges sometimes