DPPt/HGSS Burmy. What's the difference? ( Wormadam Help, please! )

I caught a Female Burmy this morning, and I was wondering what the difference was between all of the Wormadam. Which is better? What would a good moveset for them be?
I'm surely going to choose either Ground or Steel. So - which of those would be better? Perhaps Steel, but that would be like having another Forretress on my team. If ground, it would just be another serious vulnerability to Ice-type attacks.
If I were to choose Steel, what would be a good moveset?
If Ground, what would be a good moveset?

And, I know this will help completely with the whole movesets:

Burmy;
Level 12
Brave Nature ( +Attack, -Speed )
Love to Eat ( +HP )

Edit

I was thinking something like this for a Ground Wormadam:

_Chesto Berry_
( Moves: in order of use )
Double Team
Toxic
Earthquake
Rest

( Your basic Shuckle moveset, I believe. Although, I don't think she has the awesome defenses that a Shuckle does. )

But it has it's obvious defects against steel, rock, and ground type pokemon.
Although, Earthquake can hit some of the better steel types. Just not Skarmory.