Conflicting Invisalign recommendations

I have seen two different orthodontists for recommendations on Invisalign. I am 28 years old and would prefer to go the Invisalign route. I first saw a regular orthodontist who told me that I am not a good candidate for Invisalign because the crowding is too severe; it would take up to two years to correct and I would need braces at the end of the treatment. They quoted me almost $8,000 CDN for Invisalign vs. $5000 CDN for traditional braces.

I then went to an orthodontist who is one of the 'premium Invisalign providers', and he had no doubt that I was a candidate for Invisalign and told me treatment would be one year and the cost would be $6,000. I am really confused because these two recommendations are so conflicting! Do you think the Invisalign ortho was just trying to get me to sign up, knowing that treatment could take much longer and be more expensive?

Has anyone else received conflicting recommendations? Any help would be appreciated as I would just like to get started on treatment, whether it's regular braces or Invisalign. Thank you.