Both have always had question marks about their work ethic but Horton has been the better player over the vast majority of their careers. Lupul had a great year on a weak team and Horton was injured. Horton easily if he can get past the concussion.
Career wise and overall paying ability it goes to Horton in my opinion. However with the concussions and Lupul having a career year last year I can see why people would go with him, but again, I disagree.
I think if Lupul can maintain the confidence level and focus from the past season he's a better bet than Nathan Horton, who with his concussion and power forward related ailments might (unfortunately) have seen his peak already. The shelf life for injury afflicted power forwards isn't that long.