Never was a big fan of Kotipelto, even those high notes from back in the day sounded a bit silly to me. But I only got into the band in recent years. When I saw them in 2013, I thought it was a great concert and the vocals sounded good live. He does have a nice vibrato for the type of singer he is, a lot of metal singers push way too hard into and and have veeery wobbly vocals as a result(especially when they get older). Anyways, despite thinking the same about his vocals judging from live clips, actually seeing them was great and I enjoyed his vocals during that concert.
Buuut, I agree with gazinwales that his vocals are better with Cain's Offering, somehow the vocal melodies on both of their albums suit his voice better. And judging from youtube clips, this rings true for their live performances as well.
Seeing his thread pop up made me revisit Nemesis, which is simply a fantastic album.