Any of the monkey family is dissapointing. And on personal experiance during my playthrough I fouind that Scolipede and Zebstrika, while good early on as they evolved quick, were no match for any of the pokemon from the flying gym onwards.
Tynamo though, no matter how much people tell you its not worth all the effort of raiseing, its fantastic once it reaches final form. Sawsbuck was similer, until it learned Wood horn it has to rely on Jump kick to do alot of damage, but once learned is amazing.
And Haxorus took a long time to raise, but even in its younger forms it could take higher leveled pokemon out easily, so not as difficult as Tynamo.