We are both in our 40's and fairly laid back cruisers. We travelled with our teenage children (13 & 17).
We have cruised with Royal Caribbean 31 times (Diamond Plus) and this was our first cruise with MSC. The main reason for trying MSC was firstly the price, half what RCCL wanted cruise only on the Splendour and secondly the itinerary was better with a port of call everyday.
We flew into Marco Polo on the day prior to the cruise and stayed at the Crown Plaza Venice East, which is on the mainland. I would highly recommend this hotel, it was half the price for a 4* hotel compared to a 2* hotel in Venice itself. Directly next to the hotel is a Train Station costing 2.80 euros into Venice.