Now that's a good card for once!
120 HP is good for a stage 2. The psychic weakness hurts, and the retreat cost is a bit heavy.
Vileplume's most noticeable trait is the body. It lets you trainer lock from both sides, even if it is on the bench. This is huge considering the fact it can literally turn the game around with locking trainers. As an attacker, it isn't the best. For three energy, you could do status or you could hit for more damage, but most likely, it will be used more for the body than the attack.
Overall 7/10 in modified, 3/10 in limited, and 5/10 in unlimited
In modified, this card does its job well. It has the potential to be very disruptive with its Poke-body, which can stop many trainer-relying decks in their tracks, like some SP decks. Since the it can trainer lock from the bench, that's another plus as opposed to Spiritomb, which needs to trainer lock in the active slot. The only problem with Vileplume is that it is kind of a not-so-good attacker, and there are multiple ways to counter it, like Dialga G and Blaziken FB. Yet, this card has potential here regardless.
In limited, this card won't do surprisingly well. Yes the trainer lock is good, but here, trainers are important for you, and locking trainers can become quite a stalemate. It is also not that much of an effective attacker either. Regardless, it isn't all that useless, as it could be useful in some situations.
In unlimited, this card is decent. Trainer lock from the bench is good once again, but the thing here is that Vilepume EX is better since it locks on the opponent as opposed to both. Still, even though that's the case, Vileplume can act as a nice surprise card in unlimited do to the trainer lock.