I am not a big massaman curry fan myself. For some reason, aside from the fact it is often a bit sweet for my tastes, I don't care for potatoes with coconut. Not sure why but I have never found a massaman that tickled my tastebuds.
Now, beef rendang is a different story - and I have been scouring the internet trying to figure out if I could adapt a recipe to use in the IP (when/if I am lucky enough to have all the right ingredients at my fingertips at the same time). It is a 'dry curry' however - and requires long slow cooking - so I guess, if I use the IP, I should use its slow cook function. I hope I have the patience to wait that long - I have been so spoiled lately by fast cooking almost everything. I have made a version (which I know is not 'authentic' but it is delicious) in my Thermomix - but that is hardly 'instant' either.