High quality serviced apartments which make a wonderful base for visiting London.
Location: If you know London you'll know straight away that this is a great location; if you're not familiar with London well trust me, Mayfair is a great base (which is why the area is so hugely expensive, even for London - the great and the good pick the best places). But even though you're in the heart of town this area, Shepherd Market, is like a cosy little self-contained village; you're minutes away from places like Park Lane, Piccadilly, Green Park, Bond Street and yet you're in a quiet little street with useful shops and great restaurants quite literally on your doorstep. But it's not a neglected backwater - taxis are plentiful so if you're aiming for somewhere a little further away (maybe Harrods or Buckingham Palace or Whitehall or theatreland) a taxi will get you there in a few minutes.
Facilities: The apartments are all similar, with slight variation in size at different costs, but all give you the key needs of a comfortable bedroom, an elegant sitting room, an adjoining dining room area, kitchen and bathroom; naturally these days you get wifi too. The top of the range flats have a generous covered balcony as well and big flatscreen TVs. To get the same floor area (admittedly somewhat more luxurious and with room service) you could go to the Dorchester a few minutes away and pay upwards of £4,000 a night. The website pictures are accurate; slight variations in furnishing styles between different flats but the pictures don't mislead. The sitting room is big enough easily to accomodate a fold-away bed if you need to sleep three (and the fold-away is actually rather comfortable) and the dining table seats four elegantly, six sensibly. And in the kitchen, if you're staying for a few days, it's good to have a dishwasher and a washing machine and a microwave and an oven. But if hard work using any of these is not your thing you can eat at a good restaurant or pub or get a takeaway, or drop stuff off at a same day dry cleaners, all just moments away, or leave the used cups for the maid to wash. Which leads to the staff ...
Staff: You get a family feel straight away from a patient, welcoming, hard-working team. At times you might have to wait a few minutes to get help (this is a small establishment so if the enormously helpful concierge is helping someone else for a moment you need to be patient) but it seems nothing is too much trouble. The maids are equally helpful and keep your flat clean and tidy every day.
Problems: Well there aren't any serious problems at all. If you want to be picky you could say you don't get much of a view from your balcony (but you could always wander off for a walk to see the sights). If you've a flat at the front and you like open windows then occasionally you might hear over-happy drinkers on their way to a club, but you hear that pretty much everywhere in London. You migt be very unlucky and stay on a day when the lift is out of service when your room is on the 4th floor (yes, you've guessed - it did once happen to me). You're unlikely to be able easily to book for a single night.
Summary: All in all I'd recommend Hertford St - I stay there for a week each month and I've had few problems and a consistent welcome. For the visitor to London it's ideal in so many ways and it's most unlikely you'd be disappointed choosing it for the comfort and you'd unquestionably be delighted for its location.