First, some context is important. I love to go on cruises. I have been on more than 20 of them and have enjoyed them all. However, the variability in the experience is huge.
Celebrity speaks incessantly about what a high quality line it is. Instead, from my experience with them,they are an average cruise line that overprices its product. In brief, Crystal or Oceania are much more distinctive cruising experiences for similar prices.
The Infinity as a ship is comfortable and clean; the staff are especially and genuinely friendly. The rooms are small, but adequate. The public rooms are spacious and inviting.