This was our fifth cruise, and our first on Silversea or any small ship. Our main reason for choosing Silversea was looking for a smaller ship. I was less focused on the "luxury" or all-inclusive nature, although these were nice to have.
Overall, we enjoyed the small ship experience. Embarkation was quick and easy, and we were meeting with our butler (Kumar) right away. Our luggage arrived quickly. We never felt like we were part of a "herd", with the possible exception of the muster drill - the only time we really ever saw a lot of people gathered at once. Disembarkation was also smooth - we got the time slot we selected, we waited comfortably in the bar area, and walked right off when they called our group.
It was very nice being able to get in close to the ports. In particular, we were right in the center of St Petersburg, on the Neva River, whereas the big ships were far away in the port.
Cabin 606 - Good size, we liked being near the front (I don't think midship is a huge advantage, other than a slightly shorter walk) and near the Observation deck, where we got coffee in the early mornings, and the fitness center.