I've stayed at Twenty One Whitfield a few years ago and loved my experience then, but I'm sorry to say that I can no longer recommend them if you are a business traveller who requires high-speed internet. The highest internet speed in the room I was able to get during my current stay is 0.95 mbps download and 0.91 mbps upload, which is inadequate for most video conferencing or video streaming, and extremely slow in general where it takes ages for average web pages and mobile apps to load.
If you need a stove, make sure to double check and see if they still offer any rooms with them and request that particular room. That was one of the main reasons I'd booked this property again, but it sounds like only some rooms have them now.
Housekeeping and maintenance has room for improvement. (I'm mid-stay right now, and will update this review with more details depending on how they handle the points they've missed, which includes forgetting to provide utensils/plates/bowls and not delivering them after requesting them, and not fixing the shower head or following up about its status.)
Overall, the location is good, close to many local restaurants and the MTR; the view is wonderful; and the bed is comfortable. If you're not picky with housekeeping and maintenance, and don't need strong internet or a real kitchen, it's a decent place to stay.
For business travellers who need high-speed internet: I ended up purchasing a one-week pass at a co-working space one block away (Metropolitan Workshop Tin Hau) for $500 HKD. They allow you to access the space 24/7 after you sign a contract. Perfect for when you need to have super early/late conference calls and your hotel internet fails you.