Please explain this item choice

I was watching a game between Arrow Gaming and Titan, where Titan picked up a Viper to fight Invoker mid. JoinDOTA's commentator, The Capitalist, mentioned that he expected to see a fast Mek on Viper. I'm not fully understanding why Viper would pick up this item. Can someone please explain to my why Mek could be a professional item choice on Viper?

Thanks.

It's a pretty common pickup on professional Viper players, hell, even advanced players and intermediate players get it.

The idea is that you want whoever build the Mek to be able to use it when needed. In most low level Pubs, it's up to the Supports to build it, but with little HP, if they gets Focused, they can easily be Killed before they can even use Mek, so what's the point of getting it on someone Squishy?

Viper is not only Tanky enough to survive long enough to get a Mekansm off in most Teamfights, but he also doesn't have any Mana Problems. Sure he has his Orb and Viper Strike but he should always have 150 Mana to spare if he knows how to manage his Mana.

Aghanim's Spectre is another popular Item on him, since it increases the Cast Range and lowers the Cooldown on Viper Strike, add in the fact that it goes through Magic Immunity, e.g. Black King Bar and you havea Spammable long range Spell that can cause an opponent to practically grind to a halt.

Mek is a common choice on tanky/orb mid heroes which have no healing spell, this way they get the tankyness of a vang while providing a fast heal for their team, for a competitive 4 or 5 player a mek is a 25 min project while it takes less than 10 min for the mid to get.

Mekansm offers great survivability (armour, stats and burst heal), and the sooner you get it, the more effective it is (when heroes have 750hp, 250 heal is a third of their health, if they had 1500, it's only a sixth). It's great for early pushing and team fighting.

By getting it on a "core" (farming) hero rather than a support, you can get it much sooner, as the support won't be able to get the gold in time. Viper is a semi-carry, so the item helps him anyway as he'll be fighting early, and it doesn't slow down big farming items like it would on a "proper" carry.

Mekanism is the vanguard for ranged heroes. It is NOT a support item.

Outdated viper builds usually included a vanguard, but becouse that item is generally underpowered and even worse on ranged heroes there is no reason to get it on viper

Mek is better than vanguard on almost all melee heroes too.

Very similar cost but Mek has a far softer buildup. More total HP if you include the heal (only costs 85 mana after factoring in the +5 INT boost, nearly every hero can afford this), more physical EHP after ~20 minutes due to VG damage block not scaling, and your whole team gets the heal and regen instead of just you.

Pretty much all professional games will have the #2 or #3 getting the mek (unless there's a greedy #4), because they're the ones that can get it fast, and it's most effective when the 250HP heal is 1/4 or more of everyone's HP pool. Stark contrast to typical pubs which will have the #5 get it or no mek at all.

Kappa