The earlier two reviews are entirely on the money. I've known this piece for a few years now, though only just compelled to make some comments, having just listened to the Concerto through some decent kit (Sennheiser HD555 earphones, best purchase ever but that's another story...). If you're a fan of the clarinet you need to hear this concerto - Lindberg pushes the boundaries of the instrument, a challenge Kari Kriikku rises to with apparent ease, at times producing delicate sonorities of great beauty and at others sounds that can only be described as magnificently grotesque. It's all about contrast, and exploring the instrument, and it surely enough explores every single capability.
The other reviewers touched on the accessibility of the work, compared with earlier Lindberg, and it is a good point. I, for one, am glad of this apparent softening of Linberg's harmonic language in his later years. Now at last we have a composer with a modernist's palette, moulding his more edgy techniques and sonorities into a beautiful, warm, and tuneful soundworld, which verges on the romantic (certainly the concerto has a glorious 'big tune' climax).
Listen to this, then listen to Linberg's fellow Finn Rautavaara's own recent clarinet concerto, and sleep soundly in the knowledge that 'classical' music is alive and well in the 21st century.