I was going to buy an A5 for a 2nd system in a house I was renting. The speakers I had were very efficient so I called MF and asked them about the A3.5. They said the preamp section was the same and that the amp its basically the same with less output transistors. Taking that into consideration, this is what I can tell you.
The amp (3.5) had all kinds of power. Obviously, the 5 should have more.
You will never, ever, mistake it for a tube amp. Its the complete opposite.
Its also worth noting that these are the first products MF started to make overseas. As a result, they definitely sound like it. If you have ever heard their older products, you wouldn't think it was the same company.