Thundurus is extremely frail, so with that said, anything faster will practically OHKO it depending what you have on him. I'm not saying he's bad in this case, I'm just saying he's not the best. Thundurus is extremely hard to stop with a few nasty plots and the proper team to support him, other than that, meh.
Let's talk about Thundurus' competition, in this case: Electric types.
Here are some electric types with high stats also:
HP: Lanturn Base HP: 125
Attack: Electivire Base Attack: 123
Defense: Magnezone Base Defense: 115
Special Attack: Magnezone Base Sp. Attack: 130
Special Defense: Raikou Base Sp. Defense: 100
Speed: Electrode Base Speed: 140
Base 111 Spe, and Base 115 Atk is not bad, he is outclassed by a lot of electric type Pokemon, which is why I see a lot more electric types being used on teams than him. I rarely see him used, but that could be just me.
For one:
I could go on, but I'll leave it at this: Thundurus is a decent choice, but he's definitely outclassed.