The setting of hotel is stunning - watching the sunset over the sea from the garden is absolutely amazing. Breakfast is good - a lot of options to choose from and the pool area is also nice on a hot day. They don't have umbrellas but you can find shade in the garden. It's relatively quiet and peaceful.
The rooms, on the other hand, are really outdated and definitely not what you should be paying this price for. While it should be an upscale resort, everything inside is very old and nothing seems to function properly - we had issues checking in because the tablet at the reception didn't work, the air conditioning didn't work, the printer didn't work, the wi-fi code didn't work, etc. We also had ants in our room and while in general that doesn't really bother us (it's nature after all :)), as a general rule, you should NOT have ants in a hotel with this price.
The restaurant at the hotel is ok but the location of the hotel itself makes it very difficult to get to any other place (especially at night when you have absolutely no lights and very steep and narrow roads) and if you are staying for more than a couple of days, dining at the hotel just gets very boring.
Also keep in mind that you will not be able to leave or come back to the hotel without a car and parking in Santo Stefano (or anywhere in Monte Argentario) is a nightmare. So if you just plan to stay at the hotel and relax, that's ok, but if you want to explore the area, it's not a good location for that.