Played with a guy this weekend who came on the mic and said "don't freak out, I'm going to pick techies". Half the team groaned in frustration and then he said "no, I promise I'm a decent techies". He destroyed so hard. Haven't seen a techies dominate so hard since before the nerf.
He is an unconventional hero, and pre-nerf he was my favourite hero (I had like an 85% win rate with him or something) but I still insist that a good techies player can absolutely decimate a game.
That is the thing with the hero. He forces you to play a totally different way to normal. Like Deadmanza said... He can countered, pretty easily... But sometimes the lengths you have to go through.
I still want to pick a Riki into a Techies, get quelling blade and just follow him around and demine everything that he plants xD