I have an SA-155. It's about the size of a hardback novel, and kind of cool, but it would never power my main or only system unless I was living in a travel trailer or a boat, or somewhere that space was at a comparable premium. It puts out about two watts per channel, which will drive efficient speakers pretty loudly, but leaves nothing for headroom. It does have a built-in phono preamp, and can often be had for as little as $25 on e-Bay or even less at yard sales. I also have a small tuner and cassette deck and Minimus 7 speakers to go with it. I couldn't find a cd player to match, so I got a little Magnavox dvd player to play cds on my mini system.
Like I said, it's kind of cool, but more because of its size than its sound quality. I'm unfamiliar with the Sony.