Dear Julianne,
I have tried the Ampersand panels and found them too hard for the way I tend to work. The amount of give you like, and the way you work has everything to do with whether a surface is right for you.
I have been working on Wallis paper mounted to board for years, and it's definitely the surface I like best, since it lends itself to underpainting without buckling or getting its tooth filled up.
Recently I have been using the same ground for oils, and love it. You might try the thread that Sharon Knettel's started on Substrates
here
Good luck!