I wouldn't think there would be any reason to choose ORB on the interior just because that's what you have on the exterior. Although ORB can sometimes look black, which would be fine IMO with the brushed nickel, I'd be inclined to choose knobs that match the lighting and pulls.

I am dealing with this right now! We chose brushed nickel because getting matte black everywhere would cost like $7k(this would include all doors, lighting and kitchen/bathroom fixtures); our builder does offer brushed bronze for like $500 for everything. I don't like ORB personally so didn't want to get it just to get it.

I do know people are mixing metals A LOT these days. Black matte with champagne brass or ORB with brushed nickel.

We plan to change the guest bathrooms to matte black everything; yet the rest of our home will be brushed nickel, as far as the other doors and light fixtures(until we get the mooshie moosh to change them). Unless, everything is all the same throughout your home, mixing metals is going to happen. Exterior does not have to match interior. I would treat these as completely different spaces in regard to fixtures and or color choice(psst, black matte exterior/brush nickel interior for us because this is affordable at this time due to financial restraints). Will post pics in 1/2 months when completed.

So, I guess the real question here is, do YOU like the look of mixed metals? :D

I have chrome in my bathrooms and kitchen and ORB for all door handles. Yes you can absolutely mix finishes.

Yeah I would definitely go for matte black with brushed nickel., not convinced orb with br tho. Architect thinks it would be weird to see doors near each other with mixed metals. But which is worse, mixed door knobs near each other or mixed door knob next to cabinet hardware and light fixtures? idk!

I have ORB for all my door knobs and chrome in three of my bathrooms. Totally fine.

The orb is also on the interior of the exterior doors.

I have matte black doorknobs and hinges throughout my house.

In my kitchen and bathrooms, I have either polished nickel or chrome cabinet hardware. My light fixtures in those rooms are also either polished nickel or chrome. I used light fixtures in the same color as the cabinet hardware and faucets in individual rooms. In two rooms that are open/adjacent to my kitchen, I used black hardware on builtins and black light fixtures.

I think it is acceptable to mix metals but this was my comfort level as far as mixing.

as far as orb hardware..find out if your knobs have an unstable finish (living finish). If so, make sure the change in color after wear doesn’t bother you. been there, done that.

Oh I love the living finish!