Caffe Nero

Definitely understaffed. But quality of espresso is not bad at all. If you want a decent espresso from decent beans, this is still better than Starbucks or Costa. This particular location is convenient. Good music list. In fact, a much improved music list! The music list of Starbucks around the corner (its main charm until recently) has gotten worse while Nero is now not only a spacious non-touristy place but also a nice venue to relax to good music. It is not on a busy street and is not very touristy, which helps preserve the ambience and prevents it from being overcrowded on weekends. Starbucks around the corner feels tiny in comparison (and its music list no longer offers a unique charm). Also the quality of clientele at that Starbucks has deteriorated.

Probably the most spacious coffee shop in Mayfair (or at least around Green Park for sure). It's a good venue to catch up with friends/associates as it's always easy to find a seat, apart from may be the busiest hours. The service is decent, but otherwise it's your typical Nero, which I generally don't mind

Of the three chains, I think this is the best coffee you can get. Caffe Vergnano 1882 is the best I think but you have to be close to it! This store is crowded and usually understaffed. But if one drinks here and is a socially minded citizen it is pretty easy to pick up after yourself and leave the table clean behind you. I always return my empty cup to the busy staff at the coffee bar and they are always super nice and thankful for it.