If you want a really good guitar I'd say you should look for a used USA Hamer. Suitable models (shredders) would be
Californian, Centaura or Chapparel. Their quality is amazing!!!! And you wouldn't belive how cheap they are these days. You should be able to get one for $500 or with a little luck maybe even cheaper. They're all handmade....
BUT don't mix them with the Slammer series!!!! Make sure it's an USA model. Check the eBay. I have a USA Hamer Phantom myself and I can't say a bad word about it. I also have a '91 Ibanez RG770DX which is a killer guitar too so if you want to choose between the two you mentioned I would say Ibanez. Just make sure it's one of the older ones and that it's japanese and not korean.