The first thing to know is Sweden is obsessed with the alcohol content of beer. You can buy beer in the grocery store if it is 2.8 or 3.5% anything higher than that you have to buy in the state run liquor store called Systembolaget, for comparison a Coors Light is 4.2% and a Corona is 4.5% . At home I honestly never thought about what percentage my beer was and since it does not matter where it is sold and it is actually hard to find the percentage labeled on the bottle which is mandatory in Sweden.
Now that I have been in Sweden I am starting to get into this whole percentage thing, mainly what I care about is the price difference. If it is say a Thursday and I just want a beer to go with dinner I think buying the cheaper beer at the grocery store is the way to go, even for a quieter night in with friends I will still say lets get the cheap beer. My husband will agree that if it is just us cheap beer is the way forward, however if we are going to be with friends it needs to be beer bought from Systembolaget as it is a status symbol.
One other oddity in Swedish drinking laws is that you can go to a bar at 18 and drink and can buy cheap grocery store beer, however to to go Systembolaget and buy beer, wine, or hard alcohol you have to be 20 (edited I originally wrote 21 as a reflex since that is the legal age in America). I find this to be very odd since you could go to a bar and order say a Rum & Coke at 18 but to make said drink at home, which presumably is safer, you have to be 20.
Hope you enjoyed this and let me know if you have any questions on systembolaget!