Energies are more common in coh PvE.
Would have to say, alot of people don't actually bother with either, and think about picking up Aid Self instead. The resistances they gave aren't very good for a Scrapper, and I've either taken them and single default slotted them, taken one or the other, or not bothered at all, and I don't think they've really made that much difference either way.
Defiant 50's
Many and varied!
@Miss Chief
Ive already got aid self in my build im going epic less so i have powers to spare.
Its either one or the other.
If you've already got tough hide and Resist Physical... go with the energy one.
Personally I'd rather take Focussed Accuracy tho (or given INV's endurance issues Conserve Energy...) 
Inv dosnt look like it has endurance issues from the stats im looking at.
Any one else got a take on this?
Thanks
Inv has alot of toggles (you'll usually be running 4) but it really depends on your Primary. Before I got Stamina my tray was full of blues before every mission. I was a total End HOG. Something like Claws/Invuln or Katana/Invuln wouldn't have too many issues, I had to slot an end redux into every attack and toggle I had just to keep my head above water. Now I'm at lvl 50, I have Conserve Power to help when I'm running Focussed Accuracy, and the accolades that give +End also help loads.
I've you've got powers to spare, I can highly recommend the Presence pool, Fear is a very powerful tool, both PvE and PvP, should you be so inclined. The ToHitDebuff from Intimidate and Invoke Panic will work really well with invincibility.
Defiant 50's
Many and varied!
@Miss Chief
As the title says if you had to pick between the two which would you go for. My scrapper will be Claws/Inv
My first thoughts were go with elemnets as there's a fair bit of fire and a smidge of cold damage.
Then I thought oh what about the Crey, Freaks and COT who do Energy and Neg damage.
Anyhow which would you say I would get most benefit from.