To me, apart from the title track, Painkiller isn't all THAT different to Ram It Down except for having WAY better production. Most of the songs are still mid-paced arena style heavy metal tracks like most Priest (Hell Patrol, Nightcrawler, One Shot At Glory, Between The Hammer & The Anvil, All Guns Blazing, etc). Metal Meltdown is a little thrashier but probably the best song on the album in my opinion.
The only complaints I've really heard about Painkiller is that the vocals are too screechy, but again I think that's only on the title track that they are even screechy at all.