Shiny surfaces are harder to keep looking good than matt because every wipe and fingermark shows. IMO this included stainless steel but i agree, very hardwearing and hygienic. I agree absolutely about smooth, non panelled or rebated doors. We used a designer when we had ours done and he was excellent, suggested things we wouldn't have thought of and really drilled down to what we actually wanted as opposed to what we thought we wanted. He said so far as colours go, find something you absolutely love and use that as a keynote to reference everything else back to. make sure you check colours in natural light with the actual item, not a photo or catalogue. many shops will have samples that you can borrow on payment of a deposit.
Stupid story, we wanted grey floor tiles. hadn't got the worktop and cupboard samples with us (we had to share with other people using the same shop) so we borrowed the tile sample from the tile shop and nipped back to the kitchen shop to put it against the other stuff there. Nice lady who wasn't our designer but his business partner said "well those are nice tiles but are you sure you want
purple?" Sure enough, what had looked grey in the floor tile shop was undoubtedly purple in daylight. If I hadn't seen it myself, i would never have believed it.