If guilt is the only thing giving you pause and not your budget then I say go for it. I have sailed Celebrity, though years ago, but SS is nicer in so many ways. Service, food, beverages, staterooms, staff to pax ratio. The all-inclusiveness is a big factor as well - gratuities, beverages, excursions. You will sense the difference in comfort and luxury as soon as you board the ship though your very first impression may be surprise at how small the ship is. You will not be thrilled with the casino or the entertainment but as you say, you’ll be in the Med. and the cruise is port-intensive. You won’t be bored.