za.ch: Speed tanking > shield tanking :p
Careful there... Speed can get you killed easily if you don't know how to use it. Do a 180° turn at full speed and then try this maneuver again with less speed. The difference? The faster you are, the wider your arc. Try a looping in an A-Wing to get behind a TIE bomber and you'll soon see green bolts hitting your canopy, because the bomber will end up beeing "above" you, easily following your path with its lasers (or waiting for a torpedo lock).
Another problem with speed becomes apparent when you're facing cap ships. Your guns won't fire faster just because you're flying faster. The faster you are, the fewer shots you'll send towards your target! And every single strafing run is dangerous, so you want to do as few as necessary.
Another problem with speed: It's harder to evade shots coming from ahead, because they're "coming faster". And if you're caught by a stream of laser bolts coming from ahead, you'll catch more hits before you'll be able to pull out (and this with weaker shield oO).
Speed is great - in short bursts! But be careful with constantly flying too fast.