It has two good attacks. The first, Quaking Punch, requires 2 Colorless Energy (or a Double Colorless Energy) and deals 30 base damage. However, it also prevents your opponent from playing any Item cards from his or her hand during his or her next turn. That can definitely serve as a drawback for your opponent.
The second attack, Grenade Hammer, costs 2 Water Energy and a Colorless Energy. It deals 130 base damage, which is already powerful. However, it also deals 30 damage to 2 of your Benched Pokemon, so there’s fairly serious backlash for using it. Because of Seismitoad EX’s raw power, however, and being a Basic Pokemon, it’s possible that the damage to your Benched Pokemon may be well worth the impact of Grenade Hammer on your opponent.
Its first attack also combines fairly well with the Garbodor from Dragons Exalted:
Seismitoad EX is an excellent and powerful EX Pokemon for your Deck, as long as you build around it carefully. There is also a full-art version of it available, as well. As far as pulls from this set are concerned, Seismitoad EX is definitely one of the best pulls you can get.