I wouldnt call him a support... with piss poor INT growth and sad mana pool, you cant support anyone....hes is more of a TANK, great chasing potential and surviver.
I havnt tried it in Dota 2 but in Dota 1 u can manually activate the ulti, so that u dont die by burst damages or you wanna activate before u reach the dreaded 625 HP mark

Sometimes huge crits can kill Abbadon right away before his ultimate triggers. However spells like Laguna Blade or Finger of Death will always activate Abaddon's ultimate.
Usual builds for Abbadon is Durability,Survivability and chasing power. Soul Ring ,then Armlet+Phaseboot+MoM..the staple build of Abbadon in any form of game, be it cm tourney,pub or even 1v1 lol...Once you stat hitting an enemy,(with passive 3rd skill) not only is he slowed, people hitting him becomes fast(both AS and MS). Yup, even creeps start hitting fast to the enemy hero. Doesn't speed up towers though...
Anyways guys, at what ping do you all play? For me my ping shows 140 ms yet i lag