SAS are probably the most punctual airline I fly with, but this comes at a cost, the service is very expensive, there seems to be no limit to how much they charge on some routes, the price for an ECONOMY return ticket from Manchester to Stockholm can be as high as £900 during busy weeks, meaning I often use lufthansa via frankfurt instead even though this service is a lot more inconvenient and very prone to long delays.
Service on-board is hit and miss, the cabin is not always cleaned properly (dirty tray-tables eww...) and the food can be a bit mediocre considering it's price.

On the plus side, ground services are excellent, they have fast track security in most airports, the SAS lounges are normally quite nice and checkin is always quick and efficient. They are very good at recognizing their frequent flyers - upgrades are frequent on busy flights and when flights get canceled due to fog, storms, volcanoes etc. they do a good job of making sure their frequent customers get priority on waitlists.