Go with the DX 09 Keaton Batman, you won't be sorry.
I have every Hot Toys Batman figure, including the DX 09 and Toy Fair Begins and I gotta say, the DX 09 is superior to the Begins in almost every way. In fact, I'd go as far as saying that the DX 09 is better than the DX 12. The DX 09 doesn't need any mods and has a fantastic cowl and mouth headsculpt.
The Begins figure has a crappy suit, broken ankles and has a finish that flakes off. It also has a garbage cape (only looks great with a custom cape) and a weird cape clip attachment. It also doesn't help how expensive it is on the secondary market.
The '89 DX 09 Keaton Batman only has ONE problem, the PERS panel seam on the back of his head. However, if his appearance from behind doesn't bother you though, it's a none issue. The headsculpt, suit/body, cape and accessories are all fantastic.
Toy Fair Begins Batman also has literally the same accessories and weapons that your DX 12 Batman has except the DX 12 Batman's are superior. With the Keaton Batman, you're getting all new accessories/weapons. A new grapple gun, a new Batarang, bombs, ninja stars, etc. etc. You already have a Bale version, so ask yourself. Would you rather have a variety of both Keaton Batman and Bale Batman as bookends, or two Bale Batman figures?
Vs.