I have no preference if my physicians are in a suit, scrubs, or something that is comfortable while they still appear professional. I have seen mine in the full suit and tie with the cuff links and scrubs, polo shirt and t-shirt with either slacks or jeans. Shoes, everything from dress shoes, OR clogs, cross trainers, cowboy boots with the pant leg over the calf portion of the boot, birkenstocks, though never have I seen flip flops.
I say this as working alongside physicicans, being a patient in their office, to being inpatient at the hospital. I prefer my physicians to be comfortable in what they are wearing. At the end of the week on friday, checking in on their patients who are inpatient over weekends and holidays, if they still look professional, well groomed, dress down and be comfortable.
Ever wonder why some exam rooms are ice freezer cold? Take a look at what the physician is wearing as well as the nurse and the rest of the back office help. The nurse and her assistants run and get a work out.
As for them wearing jewelry other than a watch and ring, if they look good in it, if its tasteful, enhances their appearance, I say let them wear it if they choose. Their choice in clothing professionally and casual to wear in public and patient care is as individual as the stethoscope they choose to use.