Looking to replace the strings on my 6 string ibanez Sr506. I play mostly metal.
For metal? D'Addario Pro Steels.

Personally I play - and love - DRs. I'm into a smoother, more refined kind of tone, and DRs are ideal for that. But they're not ideal for generating the aggressive grind that works so well for high-octane hard rock or metal.
For one thing, DRs are NOT roundwound, as everyone seems so fond of saying. They're compression-wound, i.e. roundwounds that have been put through a set of high-pressure rollers to compress the surface of the outer wrap. No wonder they sound smoother: They are smoother!

MM