My "main" is marth... but im slowly switching to poke trainer.. if i already didnt switched. PT is by far the funniest character to use IMO . You have 3 movesets to use in one battle, very unique ones.. (one of the pokes always fight in 4 legs,,,something never seen in smash before). The other one is a dragon (what can be more awesome than this?) and the little turtle has one of the weirdest physics in the game.
But to use PT u must be aware that is one of the toughest characters to use.... because u will have to adapt to 3 diff styles and know how to apply them. Even when this is good to have more options,, it will also mean that u will almost always have one weak link against a character, so u must know very well ur match ups to know when is clever to switch a poke, even if he is ur best.
Also u need to take in consideration that even when u have 3 styles in one to use in a battle... there are characters out there that have one moveset which is better (or lets say, more effective) than the 3 of the pokes.
The fatigue is another factor that can be decisive and will annoy you in battle while none of ur rivals will suffer from this...and will use this against you.
Youll find that there are lots of characters that can deal good damage to PT with ease (ivy and zard are very comboable if played carelessly), while ull have to work a lot for ur %.
In summary, ull have to be always much more carefull about the fight than ur opponent.Is not easy task.
But to answer ur question, definitely YES. If you play the character because u have fun with it, and dont mind about losing a lot at the beggining.... ulll understand how awesome is to kick butt with Pke trainer when getting better with it.
Having 3 movesets can be bothering sometimes.... but the good part of it is that if u spend enough time to get the 3 pokes to a decent level.. ull always have a trick under ur sleeve, as the options with the 3 put together are a lot.
The full potential of the PT has not been shown yet, and we are very sure that someday one player will use PT in a very competitive level.