RE: Consistency<versus>Techs
It depends on the type of deck that you're running and your local metagame. Certain decks like VirGen function best without techs, while Aromatisse can benefit from them greatly. A deck like Aromatisse is essentially made of techs; you focus on the ones that will give you the advantage in the current matchup and disregard the others. As we've seen from Pooka's deck, which when undefeated at Vancouver Regionals, this sort of a deck can pack a real punch in the hands of an experienced player who's had ample time for testing; techy decks like these are not easy to master.
Rogue decks in general focus on techs, as their goal is to counter specific common threats in the metagame. This is essentially a different philosophy of deckbuilding and play style, compared to playing "all around" cards and getting the same setup every game. Part of the success of decks like these is their surprise factor, especially with most players having tested against the metagame and have difficulty responding to something unfamiliar.
On the other hand, a lot of the commonly played decks do better without techs. Yveltal, Virgen, and Plasma are based around playing specific cards as quickly as possible, every game. They're not trying to exploit your Pokemon's weaknesses (though a bad matchup can certainly lead to that), they're just using fast and efficient attacks to rack up damage as quickly as possible. Putting too many techs into these takes space away from searches and draw support, and clogs your deck. That's why most of the big event winning VirGen decks (among others) tend to have rather straightforward lists; they can get what they need when they need it, and nothing is clogging them up.