I think Mr. Mime is one of the best Pokemon out there. His attack and Sp. Attack stats are really high!
Mr. Mime's Base Attack: 45. (The average is around 85-90)
High? No, no, no. The Psychic hiarchy looks like this.
ABRA/KADABRA/ALAKAZAM: Hits hard, fast, has a bad movepool though (STABd Psychic is more powerful than SE Shock Wave)
DROWZEE/HYPNO - MR. MIME: Hypno is reliable, Mr. Mime has a pro (Good movepool) and a con (Must get abra, then trade it for him), but they are about the same.
STARYU/STARMIE: Great movepools, hits hard and fast. Exclusive to LG.
JYNX: Gets EXP faster and is fast, and has good movepool.
EXEGGCUTE/EXEGGUTOR: DECENT movepool, can take a hit and dish some out.
SLOWPOKE/SLOWBRO: Slow, have a good movepool, can take hits, not as powerful though. Same type as Starmie. Exclusive to LG.
Obviously post Elite Four stuff (Xatu, Mewtwo, Wobbafet) is worse.