This is a small apartment which has everything you need, even for an extended stay (dishwasher, clothes washer, fridge). It's right at the heart of Alfama -- very easy to go out and explore, and not just Alfama, if you like walking. The nearest train station and metro station are 7-10 minutes walk away. You can take a train to Porto, for example. It's only 3 hours. Sintra is also less than an hour away (but from a different train station) or just use Bolt or Uber.
The apartment is very quiet at night. I did not need my earplugs. If you're tall, remember to mind your head when leaving the kitchen or the bathroom.
The Wi-Fi is decent, but only 802.11n 2.4 GHz and thus tops out at 25-75 Mbps (depending on your device), and fluctuates due to other Wi-Fi networks nearby. If you need a guaranteed fast Internet connection, bring an Ethernet cable and you'll get 100 Mbps up and down just fine.
The bakery downstairs is a plus: you can quickly grab a coffee and some fresh pastry, from 8am.