Grouchy Smurf is one of the more prominent Smurf characters in the Hanna-Barbera franchise. His grouchy demeanour is his most identifiable trait, often saying "I hate [insert whatever the last person said]!". Adorned with a drooping hat, this Negative Nancy crosses his arms and shows resistance to most anything that anyone suggests. Now, on to the voice compare! I hate voice compares...
Michael Bell was the first VA to voice Grouchy, getting behind the mic for the original series and the Christmas special. Michael's known for either his superheroicleading-man voices or his higher-pitched, raspyvoices. I don't think it took very long for anyone associated with casting Michael or anyone reading this to categorize Grouchy into the 'right' area of those two choices. ;) Michael's raspy voice was a perfect fit for the character, but it's almost a little too grating, personally. I don't have a problem with the performances in the original Smurfs media, but they're all just rather high-pitched (irritatingly so) for me.
For the two live-action films, as well as the DTV Christmas special, George Lopez voiced Grouchy. The casting of George is almost universally accepted as the oft-despised "casting a celebrity for the sake of their name"-situation, and I won't deny that. He's pretty much using his own voice, but honestly...George is probably my favourite voice for Grouchy. He gets the grouchy attitude down pat, and his naturally raspy voice is just a little easier on the ears than Michael's.
Bumper Robinson took over the role for the video game based on the sequel. Bumper does fine with what he's given. The problem isn't his delivery or voice, it's the fact that his material is limited to standard video game one-liners. He manages to sound enough like George to make it passable for his rather small role in the game.