We did the 7 night roundtrip on the August 6 sailing. We are a family of 4 (kids 5 and 9), joined by a whole bunch of in-laws for a total group of 16 passengers. In order to get adjoining staterooms, we had to opt for lower ocean view rooms (2171 and 2175). This is our 3rd cruise, but first on Celebrity.
The ship itself is great--opulent but classy, no cheap kitsch. A very nice size too, as it offers the big ship amenities but not so huge that those length-of-the-ship walks become an exasperating chore. Infinity is over 5 years old, and needs a slight makeover. Not shabby or dated, but if you look closely you can find little scratches and stains and dents. But this is a detail; overall the ship looks great.
Our staterooms were roomy, well-laid out, and comfy. The bedding was fine, but the chairs looked a bit worn. The daily service was friendly, thorough and dependable. You get a fridge, but it's full of mini-bar stuff, so you can't easily keep your own water/soda cold.