This is a clean, modern, well-designed studio. The double bed (two singles combined) is comfortable, and the bathroom is also very nice. Its location directly across from Atocha makes it easy to commute and find a cab, and there was no noticeable street noise. The AC/heater works well, Airnaldo was very communicative, and overall the experience was great.
My only complaint is with the description and pricing. For the cost with fees, I expected to find a standalone studio apartment in a residential building. Instead, the building seems to be mostly comprised of other travelers and hostels, and parts of it are under construction. The elevator in the lobby is surrounded by building materials. The studio itself is inside of an apartment with other numbered doors that ostensibly lead to additional rented rooms. This appears to be common in Spain (I’ve stayed at several other places like this), but they are typically labeled as a “Private Room”, hostel, or clearly described and priced accordingly. I awoke to the noise of other guests entering/exiting the apartment.
I would still recommend this studio if the price doesn’t bother you. I think the description should be updated to reflect the above.