The two finalists are
Kris Allen.


Adam Lambert.

The American Idol title winner for season 8 however is Kris Allen. Many of Adam's fans must be disappointed. Does Kris actually deserves it? This is a hard one. PLEASE note everything written below is just my personal opinion.
Looking on the performance aspect, based on solely on singing I would rate Adam Lambert at least 8.5/10 .

Why?
1)His singing skills (Unbelievable vocal range and vibrato technique he posess)
2) His consistency in singing well week after weeks.
3) His originality in twisting cover songs to suit his style.

Under this same aspect, I would rate Kris Allen at least 6.5/10.
Why?
1)His singing skills (Acoustic style but Adam pwn here.)
2) His consistency in singing well week after weeks (is lower compared to Adam).
3) His originality in twisting cover songs (he changed songs by mainly using his musical arrangement skills).

In another aspect from the music producer view of prospect with working with the artist, Adam might score at least 6.5/10 here while Kris scores at least 8.5/10.

Why?
Kris Allen has musical background in playing the instruments such as Piano, guitar, and also, he possess skill to make musical arrangements to suit him as a singer.
Also, Kris Allen seems to be adaptable to different genre in the wide range of Pop music. 

On the other hand, Adam is solely a singer as for now. He might not understand musical terms used by music producer in the background. Apart from that, he seem to be stuck to one genre which is the "Adam Lambert style" genre. Thus, imply the inflexibility to change to market demand of song. (Remember what he did in country week?) For now his style is well received, what if in years to come is not popular anymore?

In conclusion, Adam and Kris have strengths and weakness from different aspects or perspectives. Hence, personally, I will be happy with either one of them as the winner.

By the way, I like the song Kara wrote, No Boundaries. Here is my Wolverine's cover. hahaha.