It is Swords & Wizardry Appreciation Day.
I play Swords & Wizardry with Erik Tenkar.
Well, Tenkar chose it. He's the GM. But it's a choice I'm glad he made for three main reasons:
Simplicity - Really, it's not that complicated. Or complex. It's got a little more depth to the rules that what I saw in the white box D&D set, but not so much there is a lot to learn. It's heavily dependent on GM adjudication, but it's got some very simple systems for resolution that make it a breeze to run. The rules are well-written, too, so it's pretty clear what the intent and the wording are meant to have you doing.
It's a simplicity that makes for smooth additions to the system. If you want to add some detail to a specific area, you can. If you want to port over elements of other retro-clones or D&D, that's easy. Good example? Erik uses different stat bonuses. We roll with 13-15, 16-17, 18 for +1/+2/+3. Nothing else down the line needs to get changed. Perhaps it's just as easy in other retro-clones, but really, the more that is already there the harder it is to add something on without banging into unforseen consequences. S&W had just the right level of "enough to make play go smoothly" without getting fiddly just for the sake of getting fiddly.
Versatility - Do you like Attack Bonus-based combat and ascending AC? Me too! S&W supports that. Crossed your arms and scoffed at such new-school ruinations of all that is Gygaxian and Arnesonian about gaming? S&W does descending AC and table-based combat resolution.
There are a lot of natively-supported options in Swords & Wizardry. That's what I like about it. It's not even "as written except" but "as written." You can pick and go.
Flavor - Look at that cover art (all of them). Read that old text. Look at the way the monsters, items, and rules are written. It epitomizes the old-school feel without a lot of the old-school cruft that came from exploring new ground.
While I single it out for occasionally dipping into "don't tell me what you aren't" it is does what it intends to and does it well.
I'm glad that we're using S&W for our B-Team game.