Originally Posted by Millennium
When should he be picked or not? Go PT Dagger BKB AC or use Armlet, HoT, Crit etc?
Medallion good or bad on him? Vanguard required?
What about Battle Fury for damage and regen? If you attack an enemy whose armor is reduced, does it also increase your cleave damage to other enemies?
Skill build? Does it vary?
He's a multi-dimensional hero. Most heroes only serve one or two roles, tops. Slardar is unique in that he can serve MANY roles, often all at once. He can tank, he can chase, he can gank, he can support, and he can carry. Basically, you can do almost everything with this hero. Sprint is excellent as a mobility boost, which greatly enhances your ability to chase and finish enemy heroes, or get the hell out of sticky situations. Slithereen Crush is just as good as Centaur's Hoof Stomp, if not better, since the enemies are slowed by a good amount for 2 more seconds after the stun. That, combined with the low cool down and somewhat larger AoE, makes chasing so easy with Slardar. His bash ability is more reminiscent of a carry, allowing him to deal a lot more damage and disable enemy heroes here and there. His ultimate serves a dual purpose of cutting through armor (this counts for a lot more than you might think) and revealing invisible units.
Personally, I prefer playing Slardar as a carry/ganker/pursuit/tank hero. I don't like supporting with blink dagger and whatnot, since his ability to deal damage is just so great. Str Treads, HotD, and 2 bracers is my core build, which gives him a lot of HP and damage at the same time, with decent attack speed from treads. From there, I generally branch to Yasha, getting Perserverance as well (for Bfury later). After that, it's a decision between finishing SnY or Bfury - go for Bfury if you can afford to pass up on 304 HP and the extra disable. Afterward, you should focus on either another damage item (say Buriza or Radiance) and/or a Hyperstone.
MoC is stupid on Slardar. It's an early item for cutting through armor, but heroes don't have that much armor early on, and reducing an opponent's armor too much below zero is actually counter-effective. Ideally, you want to lower their armor to exactly zero, or around zero (give or take 1 or 2 points). However, it's better to reduce a hero's armor from 15 to 2, than it is to reduce his armor from 6 to -6. You can look up the math craft, but you'll never need additional sources of armor reduction unless you're facing either a DK, or a massive tank that has or is going for Cuirass/Shivas. -16 armor is a lot.