Monahan was the more physically ready and higher iq player, but MacKinnon was significantly more skilled, faster, and just overall had the ability to take over games. Prior to 2017-2018, Monahan legit did play better than MacKinnon. But after that it was history and MacKinnon became one of the leagues best.Flames dillemas, lol...
Anyway, the answer, career wise is- hard to say... Both had ups and downs, but neither ever was what you want from your #1 C... Great options for #2c though.
BTW- as someone who never followed drafts and prospects, I was surprised to discover that Lindholm was drafted higher in a same draft. I always got impression that hype around Monahan was bigger (seen some ppl cpmparing him to McKinnon in their early days).