To start with the positives. A chic apartment in a vibrant center with good public transport links. Extra little touches like shampoo and a coffee machine being provided were great. Mario was extremely communicative and replied quickly.
But unfortunately our trip was hurt by a couple of big flaws.
Firstly, the hot water was limited to about 5 minutes of showering total. As a couple that both appreciate long showers this was a frustrating damper, and meant if we both wanted to wash our hair we simply did not have enough hot water to do so. For others this may be a non issue.
The second much bigger issue was noise/location. We got barely any sleep the first night with how loud the location is. Bikes driving past loudly at all hours of the night, a fridge that constantly makes noises and shouting from people outside. We purchased earplugs, which made the sound somewhat tolerable but as neither of us are used to earplugs: we've left with earache, but thankfully still managed to get reasonable amounts of sleep.
For us this was a deal-breaker and if we'd known beforehand we would have booked elsewhere. Having said that, if you're used to wearing earplugs or sleeping in loud environments then this may be a non issue for you too.
And finally: we had bedsheets and no duvet. As a preference we would have preferred a duvet option. Not a massive deal and would probably have easily been remedied by asking the host, but it wasn't an issue we were affected by enough to warrant asking.
tldr; bring earplugs, expect very short showers. Otherwise it's a lovely apartment with a great host.