Personally, I really liked Treecko. It may not have been the cutest of all starters, but it was pretty cool-looking. And its second-stage evolution, Grovyle, looked even cooler. When Treecko finally evolved into Sceptile, it was able to get a major boost in its Speed and Attack. And after one Swords Dance, it had the chance to become a great physical sweeper—allowing it to wipe out your opponent's entire team single-handedly. d: The only thing bad about this Pokémon, though, was that it had a total of five weaknesses (fire, bug, poison, flying, and ice), which is a lot. But if you utilized Sceptile in a good way, then it should been able to overcome these weaknesses without any sort of issues.
Out the three starters, Torhic would have to be my second favorite. I just loved how adorable it looked, and the way that it stared at you with its shiny puppy eyes brought joy my heart in an instant. Plus, its final evo, Blaziken, had a variety of moves in its arsenal, which made it very useful when battling competitively. (: