I spent 2 months in Sergio's loft / apartment. I have no regrets!
First of all, the location is great. Very central, safe area. Within 10 minutes walking you are in the city centre.
There's a lovely park only 2 mins walking away, Estrela, a gem.
And a good supermarket literally around the corner as well.
The apartment itself is perfect for 2 people. And it has all the amenities you'd need re cooking too.
The view! Amazing. Can you get a better view? I'm not so sure you can. You'll spend hours out on the balcony.
The host. One of the best experiences. Sergio is super-friendly and occasionally sends messages asking if everything is ok, do we need anything etc... he could not have been nicer.
The book. Read it! You don't need any other guides for Lisbon. We tried a few of his restaurant recommendations, we just kept going back to them.
To sum it up, if you're a couple travelling to Lisbon anything from a few days to a number of weeks, you won't regret booking this apartment. It will make your stay in Lisbon perfect.