Which internet provider to choose (Milan)

Hi,
I have used Fastweb internet for 3 and half years now. Was quite happy with the speed (not with anything else) for the first two years. But now we've been having issues with stability, speed and coverage (within the flat..) for almost a year. Since I have an "old" contract I pay much more my maximum (hardly ever reached) speed of 10 mega than the "new" costumers pay for Protected content .... According to the information on their website I would even have to pay almost Protected content to cancel my contract for this shitty service. The other option would be to accept their "offer" to get Protected content for an extra 5 euros per month (still making me pay the double of what a "new" user would pay for the same "service"). I think I'd prefer to change provider, not because of the cost, but because I lost trust.
I've found interesting offers with Tiscali and Infostrada, offering up to 20 mega. I wonder though, how low can this "up to" 20 mega be? And how about the upload speed that is significantly lower...... Anyone having any experience with these, or other, internet providers. I do need a very speedy internet connection for my work, and most of all, without interruptions and always covering the entire flat. Also do have up to 5 devices simultanously connected to internet..