Oh God. There is a lot of vapid journalistic hype about the Finnish education system, but that article really does take the biscuit. A collection of half-truths, downright fibs and stuff taken out of context.
Although you'll hear people saying that Finland is "the world's top performing education system," actually Finland was (if I remember rightly) top for one year in one test (PISA, a test which is tilted heavily towards reading comprehension). It has never performed better than average in TIMSS (the "other" big international education ranking, which focuses on harder-core science and maths and is considered a better test of university-readiness). TIMSS and PISA are both "good" tests, by the way, but they measure different things. Finland has only ever performed well in one of them.
What's more, Finland's big glory period is behind it--it topped the league tables in 2001 and has declined quite a bit since then. I'm not slagging off poor old Finland, by the way: my point is that a better summary of the Finnish education system is that "It is good in many ways and gets several very important things right" not "It is a magical fairyland utopia." Unfortunately, journalists tend to prefer the second story, because it's more exciting.
The biggest error that journalists (and others) are apt to fall into when comparing education systems worldwide is the "chronological fallacy." The performance of teenage students in any given year is a reflection on the education system as it was since they started school a decade ago. So if Finland was best at PISA in 2001, we need to be looking at what Finnish schools were like in the 1990s, not what they are like now. Any differences between the 1990s and now may well be the reasons why Finland has declined, and we should be wary of incorporating any such ideas into our own education systems.
The Finnish education system in the 1990s was basically pretty traditional--classes were (and mostly still are) taught in lockstep, without differentiation; desks were in rows most of the them; there was a textbook for each subject and lessons centered on bookwork and teacher presentations.
Much of this system is actually still in place, and trust me, the great majority of Finnish classrooms do not look anything like the whizzy trendy ones shown here, with students lolling all over the carpet etc. Try an image search for "peruskoulu" (Finnish for "elementary school") and you will see mostly very normal looking classrooms, with teachers teaching and students looking at teachers and raising hands.
That said, there has been a gradual shift towards a more soft-focused Scandinavian-style of teaching in Finland, partly as a result of influence from Sweden (the Finns are not Scandinavians, by the way, and have a very different history and culture). The Finns often joke that "Whatever the Swedes do, we always do it 15 years later"--well, this appears to be the case in their education system.
Needless to say, as the Finns have adopted a more Swedish child-centered approach to their education, well, the kids are enjoying it more and report that they feel more positively about school, but quite honestly, well, they aren't doing as well in international assessments as they used to (Sweden started bringing in these methods about 15 years earlier, and Swedish results, predictably, started declining about 15 years earlier, bang on cue). If people want have subject-free classrooms of iPads and beanbags, I guess they are welcome to do so, but it isn't going to make the kids better at maths, reading, or knowing stuff.
It is most certainly true that the Finns have always had relatively short school hours (late school start age, short school hours, long holidays) and homework hours compared to other countries, and this has indeed long been the case.
On the other hand, this has to be understood in context. Finnish is the most "transparent" or easy-to-learn writing system in Europe--it's easy for parents to teach their kids the basics before school simply by sharing picture books together, and filling in the gaps at school requires at most a few weeks. I personally would not recommend waiting till 7 in the case of English, which takes 2-3 years to learn how to read and write fluently.
And Finland's relatively weak TIMSS performance is probably connected to its short study hours and lack of homework, IMO. Remember, TIMSS (unlike PISA) requires students to actually do some serious maths. You don't get good at maths without doing shitloads of practice, pages and pages of it. Every single country that does well at TIMSS is serious about making its kids do plenty of maths homework.