Oh my goodness, another Constantine fan! I didn't think they were allowed on this forum ... (grinning & ducking for cover!)
I didn't think Constantine had the best voice at all, but I thought he was by far the most interesting of the bunch. He also seemed very charming in a quirky way (though he desperately needed a good haircut! LOL!). I mean, anyone who can do an old Partridge Family song and make it fun has my vote! His downfall in the competition was picking boring songs. If he picks good material (and doesn't allow his band to shoehorn him into stuff that is good for the band but not for him as an individual performer), I think he will go far in his career.
You think his song choices were boring? NO WAY! He took interesting songs and made them more interesting. He took a song like My Funny Valentine, a song we have all heard a zillion arrangements of and made it new again. For that alone he should have won! Like Bo, Constantine was a seasoned performer. He never hit a bad note and he had great stage presence. He had a better pop voice than Bo.