Third Party Lens for Weddings

[EOS10DKEN]

I am looking for a good quality lens that will serve as the primary lens for shooting weddings. I have heard good things about the new tamaron 28-75 F2.8. I have a Tamaron 28-105 F2.8 but the focus seems to be really slow. Does any one know if this has improved on the new lens or have another lens to recommend without breaking the bank?

[Cadwell]

I can track race cars with it... I'd imagine brides move slightly slower than that... ;)