basically im after an overdrive pedal and these 2 seem to be the main ones everyone mentions. whats the main difference between the 2 and is it worth spending the extra £50 for the tubescreamer cos that seems quite a lot to me?

i can get the SD-1 for around £30 and the TS9 for about £80, ideally i dont wanna spend more than £50

i've recently bought a marshall dsl and was looking to get more gain for stuff like trivium and bullet for my valentine

cheers dudes
the tubescreamer sounds better.
The Gear:

Custom Strat
Mesa Boogie Stiletto Ace
Fulltone OCD
Electro Harmonix Small Clone Chorus
Dunlop Crybaby Classic
MXR EVH-117 Flanger
Fulltone Soul Bender