As others have said, slow/deep house has been around pretty much since house music has... Some people do it really well, others don't.
Personally, for deep house not many can touch the likes of Dixon and Henrik Schwarz e.g. this is a 100% banger imo and I've seen it go off completely in clubs...
Also, Dixon's Resident Advisor podcast is about as slow as house gets and it's amazing, I challenge anyone to listen to this and not nod their head
Amp Fiddler - Faith (Jazzanova Remix)
Alice Smith - Love Endeavor (Maurice Fulton Remix)
Kelis - 80's Joint
Owusu & Hannibal - Lonnies Secret
Kathy Diamond - I Need You
Paul Randolph - Believer (Jazzanova Remix)
Demba - Louder (Henrik Schwarz Remix)
Martin Landsky - Let Me Dance (Sebo K Remix)
Telepopmusik - Love Can Damage Your Hard (Dennis Ferrer & Abicah Soul Remix)
Tracey Thorn - It's All True (Martin Buttrich Remix)
Herbert - Moving Like A Train (Smith'N'Hack Remix)