Convenient living space in a good location with basic amenities for a short stay, easy to find and offering 24/7 keyless check-in (provided you fill out all the required documents beforehand). The two negatives for me were an uncomfortable mattress and the smell - while some smell from the plumbing in old buildings can be expected, the cigarette smell coming through the extractor in the kitchen is not (we reported it and received an apology blaming “guests not adhering to house rules”).
The host company are responsive, but the communication could be friendlier - it all seems to be about your obligations and potential penalties as a guest with lots of legal speak. It is a high-volume operation with dozens of apartments in the same building, catering to tourists, so in my view not really ideal for a business traveler planning a longer stay.