It is Soccer Night in Sweden - What you need to know in 59 seconds
The strongest team historically and recently is Malmo having won the league crown 21 times since the founding in 1924. If one looks at recent history (since 2008), Malmo has won 3 of the last 7 titles and are currently vying to win their third in a row.
Tonight, Elfsborg, the last team other than Malmo to win Allsvenskan (in 2012), has a showdown with Malmo.
UPDATE: It is a final, 2-2! Sadly, the high profile game was marred by disruptive fans late in the second half. Elfsborg fell behind 1-0 but leveled before the half. Malmo got a 2-1 lead late (76 min) in the second half. Unfortunately, some Malmo fans set off fireworks in the stands and the game was halted while officials decided how to proceed. After a lengthy stoppage, the game was resumed and 20 minutes of extra-time was added. Elfsborg got the equalizer at 90+16 minutes.
Sadly, fan misbehavior remains an occasional issue in Swedish soccer. I do hope someday to see a match in Sweden but would probably not attend a contest in a large city arena where drunken fan violence and misbehavior tends to be more common.