he is amazing no matter where he goes really. it's just very different bands yield very different jorns. his work with russ on magnus karlsson's albums was amazing. his work on beyond twilight was his best ever (i don't have ark yet). i love masterplan also (first album was better, but the aeronautics is still great). my brother loved his work in nikolo kotzev's nostradamus metal opera. every guest appearance has been great as well. mundanus imperium is not so hot, but jorn is their best instrument. same with millenium.
his solo stuff is amazing also. it's a bit more rock'n'roll rather than metal.... but it's got godlike vocal lines. i have out to every nation and after three or four listens, i couldn't stop.