Our Opinion

It is hard to find a good word to say about Lisbon. We found it crowded and full of beggars and thieves. One of our number had his wallet stolen by pickpockets (which thankfully he managed to retrieve).
There are sights to see in Lisbon but our advice is to avoid the place if you can. If you can't avoid it, only travel with as much money as you need for the day and keep your eyes out for thieves. If you see a commotion of any sort, walk away from, it's probably a diversion for pickpockets.
Every time we stopped to eat or drink in Lisbon we were plagued by beggars and It didn't seem to matter whether we sat outside or inside. Prices were higher than in Faro but generally what you would expect in any European Capital city.

Further Details

Travel
Faro - Lisbon with Portuguese Railways
Public Transport in Lisbon is varied with buses, trams and a Metro system. Tickets are relatively cheap, we bought a day ticket allowing us to travel anywhere within the city. All forms of public transport are very busy and in our experience can become a haven for pickpockets