I thought it was funny that the 2 posters both picked The Mykonos Bay and they both have over a 1000 post which in my opinion makes them pretty much experts on giving advice and it was a choice that was requested and then changed and over looked.
With that said I have been on the island for 10 days now and drive by the Mykonos Bay pretty much every day as I love Ornos Beach and it is on the way from the hotel I stay, The Alkyon Hotel. The Alkyon Hotel by the way is right across the street from the Hermes and my room overlooks the Hermes pool along with the Alkyon pool the best view to watch a sunset from my patio or room. I have not stayed at the Hermes in my last 2 trips but I can say that the Alkyon has the same view, same walk and offers excellent service, breakfast and nice rooms with most over looking the town, Sea and sunset directly from your room.
The last 10 days have had a very strong N. wind, except for one day, which the Mykonos Bay hotel looks upon so the beach itself can be windy with constant waves. With that said it is right on the beach and has a nice pool with clear glass windows to look at the sea and they block the wind. It is an easy somewhat flat walk into town and close. It dose not have a direct view of the sunset as there is a peninsula across from it but if you are the type to get into town then there is your perfect sunset view.
The walk to the Hermes and Alkyon from town takes about 10 minutes and it is a hill so the ones that tire easily may not like it but it really is not a bad walk. I see countless people do it every day. I have a scooter so I by pass all that but it seems to be fine with many.
Since I have not stayed at Hermes I will not say anything bad about it but if you can get a room at the Alkyon with sea view for less I would suggest that. Just my opinion.