I tried the Answer brand tests... they gave me positives when I wasn't ovulating (was having a messed up cycle so I'm not sure if it was them or me, but hear TONS of girls complain about the same issue with Answer brand so they must be TOO sensitive for most girls). Those were strip tests... where you have to pee in a cup and then dip the test.
Mid-stream tests are ones you pee directly on the stick. I was testing while I was at work, so I couldn't deal with the cup etc, lol.
I tried First Response... first off, I bought the 20-pack figureing I'd save money... turns out they put them all in one ziplock bag and once you open the bag the first time, they say you have to use them within 30 days or they're no good...so it didn't save me ANY money to buy those in bulk. Thats the test brand where I didn't get a positive at all... got close. Heck, I even saved one and used it with the same pee that gave me a positive on another brand... and it looked the same as my last 'almost' positive.
The cheap ones online worked perfect for me (If you're in the US or canada and are interested in the site, let me know, its too expensive in shipping fees if you're elsewhere and can find one in your own country or closer). I loved that each test was individually wrapped, so they didn't have a 30 day limit, if I didn't use them all, I just saved them for the next cycle etc... And I could buy a few mid-stream tests for at work, and strips for at home etc.
Lots of girls love the Clear Blue Digital ones since they give you a smiley face and you don't have to stare at lines and figure out if they are the same darkness or not. Some girls use the cheap internet tests... then when they get a positive internet test, they use their digital test to confirm.