seasons 1-6 were gold. 7 and 8 were meh, 9 was kinda stupid because the entire season was based on robin and barneys wedding, only to break them up in the end. the 9th season could have been justified if robin and barney stayed together. that being said, the ending is not bad in my eyes, it just could have been executed so much better. if they had half of the ninth season centered around Robin's wedding, and the other half to divorce barney and robin, kill off Tracy and, get ted and robin back together then the ending would've been so much better and easier to digest, instead of giving us three minutes to digest Tracy's death, the divorce and the fact that robin and ted are together again.
robin is definitely ted's "the one" to be honest. and if you think that makes no sense, then you're proving my point. ted himself said that love doesn't even have to make sense. it's completely random and irrational.