I would second the opinions so far, we usually cruise with Royal Caribbean (and I have a lot of experience on other lines) but would recommend CMV. I did a short cruise with my elderly mum in May and it far exceeded expectations and certainly the amount paid. The food was superior compared to the likes of NCL (sorry have to speak as I have found on many cruises with them in the past!) mainly as it was tasty, HOT, not luke warm, and the staff all over the ship were so friendly, they really made our trip. We enjoyed it so much (OK it was influenced by the bargain price in a big way) we have booked to go again in August on another short cruise.
If you are looking for a flashy modern ship, great entertainment and a young crowd CMV does not deliver on these things for me, but for a cheap and cheerful break to somewhere you want to see, it fits the bill. The cabin was comfortable on Magellan, it was a bit old fashioned, but clean and the bed was comfy. I tried CMV a fair few years ago now on Ocean Countess and was reluctant to try them again (that's another story), but I think they have changed hands since then and I would recommend them for sure. Enjoy!