I think you need to understand how you will use this appliance that will dictate the size needed . I commercial kitchens we had 30 " I run acatering biz from my home and have no plan to have as team oven but i use my walloven all th time and they are 24" witout the trim and have worked for me for 16 yrs . I think the fact is the steam oven cooks faster so even multiple dihes could be ready quickly and the 24" seems to the fave for most people . My experience with them in commercial kitchens was not great just about the time we needed the oven it had some issues .I know people love thembut IMO 24" is asbig as I would go.

I think if you are interested in going wider, that you might also wish to go taller with it as well.

I have had 2 of the 24" Miele CSO XXL and I'm happy with the size. I also have a 36" Wolf Induction Range with a larger oven, which I rarely use.

The 30" wasn't available when I bought ... not sure if I would choose differently.

Our current 24" Miele CSO XXL sits below our 24" Miele coffee machine, so they stack nicely without taking up more width in the kitchen.