I agree with the simplicity aspect...it took me just fifteen minutes to generate a character...gotta love that! Combat is fast and deadly...just like in real life. You have to think before you fight...the polar opposite of D&D (oh, I have 200 HP's...I can slay that army of orcs by myself!). Sure, heroic gaming like that has it's place, but for my money you get much better roleplaying from gamers with a potentially deadly, gritty combat system.
Also the spell system. Simple and elegant, classic BRP-type stuff. I love the fact that they've keep percentages for magic spells. In my mind, magic should never be so dependable as to not call for a roll and should also be challenging (for the character) to cast, demanding a skill score.
Also also, I'm personally not a huge fan of feats and such, they can be fun but often become the only defining aspect of a character for some players (which may say more about class and level systems, but hey...). Feats also become a bother to keep up with at higher levels. Sure, they're are Legendary Abilities in RQ, which I like BECAUSE they are legendary...you have to wait a while to get them and not every Joe Mercenary has them. Plus, they're expensive...I can see most players blowing through Hero Points before they buy those.
There's more but I've taken enough space...gotta go work on my first scenario!