i think hes an awsome bassist, far to underrated.. he can atleast keep speed with muyung from Dream theatre, if not faster...
he doesnt write much songs, but im pretty shure he makes his own bass lines, he have an amazing speed(Black Diamond) and he can groove and add cool fills(listen through all of "Fantasia", it realy shows pretty much of his abilitys..)
and he plays with fingers all the time.. realy cool to see live.. i think he uses 3 fingers though, but listen to the song "destiny" in the middle of it he plays the exact same as the guitar, wich makes it sound like a little bass solo thingy.. Jari should have been more known in the metal bass society, hes not like any of the other Power Metal Bassists(wich, most are basically fast pop punk bassists...)