RuneQuest 6 in PDF and is offering a Print + PDF bundle on their website.
I've never played RQ in any of it's editions (I own Avalon Hill's 3E & both Mongoose Editions), but enjoyed running and playing Stormbringer back in the late '90's.
It's hard to explain how far ahead RuneQuest was from a game design standpoint way back in the early '80's. A Unified Mechanic, no Classes, no Levels, Skill focused, anyone could wield magic, essentially Sorcery could emulate DnD 3E's Metamagic. It's an amazing game that has evolved little over the decades, due to be so far ahead of everything else.
I haven't picked up the new edition yet, but I will fairly soon and I urge you to do the same.
Oh, and Pete Nash and Lawrence Whitaker, the architects of the new edition, are pretty swell too.