Firebird said:
I always heard that the 6 hole vintage, although not being as functional trem wise, has better sustain over the two-point fulcrum. I may have heard wrong, but it made sense to me because the vintage has more points of contact to the wood than the two-point fulcrum. I even read or heard somewhere that the vintage had less chance of warble than the two-point. By all means, anyone that likes using the trem alot shouldn't have a vintage in the first place. I agree with that.
You probably heard right, but it's not true.
That design
appears to have more points of contact, but there's no way they all make contact. Even if the body were made of metal and machined very closely, those six points would have varying amounts of contact, or pressure. It's gonna be two unpredictable major points out of the six, and maybe some amount of touching on the others. The two major points are connected to the body through some very thin posts (the pivot screws), so the connection isn't very good.
With a wood body, the problem is exacerbated, as there's simply no way to machine wood to the exacting tolerances you can with metal, and even if you could, wood has variable density throughout the grain structure. Now you have two unpredictable main pivots which are very thin running into a relatively soft base. So, you lose sustain due to absorption, which also costs you tone to some degree, depending on how much influence you wanted the neck/body to have on the whole assembly.
Then, the main contact points aren't very fine, and you have other friction points that aren't as tight and so may develop deposits or oxides, so they tend to gall and hang up, which means the thing won't return to neutral reliably.
The end result is a problem child. When they're new, they're not good, but they're not terrible. But, things deteriorate fairly rapidly.
On the plus side, at least for the OEM, they're inexpensive to manufacture and install. That's why you still see them on MIM or MIJ guitars in the sub-$500 range. And, of course, you see them on "vintage" instruments from before they knew any better and on builds by people who insist on the crummy design for reasons only they can justify. Certainly not because they want reliabilty, repeatability, sustain and tone. Although, if asked, they might cite those reasons as their motive for using the things. But, usually it's just an emotional thing. "I wanna vintage guitar! Waaahh!" Lord only knows why. They're crap.
Modern vibrato bridges use a two point fulcrum with knife edge pivots, and they're usually made of hardened or stainless steel so they wear extremely well. There's almost no friction at the pivots to speak of, so the positional repeatability is high, as is the reliability of the pivots. The load is balanced across two points only, and the points never move due to wear or substrate compression or movement. The posts are heavy and large, so the connection to the body is very solid, regardless of the wood species involved, so sustain and tone are as good as it gets without going to a hard-mounted bridge.