There is so much misinformation in this thread its ridiculous -- people who say teasers are bad bets, people who say they're good but have no clue what they're doing, someone claiming to hit 90% of each leg who probably doesnt even know how to caluclate the win percentage of said leg for a +100, -105, or -110 teaser.
If you're new and want to learn basic strategy on these pick up Sharp Sports Betting by Stanford Wong. There are subsets within the typical basic strategy teaser that can be used to isolate sides with higher hit rates as well.
In any event, this thread is rife with bullshit.