1265 and BH's very different animals. A couple questions:
1. What kinds of sites do you intend to hunt, and what are you trying to find there?
2. Do you prefer stone-axe simple stuff, or products with gobs of features?
The 1265 is operationally simple, short on "features", and goes deep on coins. It typically air tests on the order of 11-12 inches on coins. You have to learn to hunt by sounds: the 1265 has a reputation for being pretty noisy in trash which doesn't help the learning curve. It's not a lightweight (about 4 pounds with batteries), but the ergonomics are excellent which helps make up for the weight. Being an oldie, it's off warranty. Searchcoils are still available. Make sure the searchcoil connector is the metal Switchcraft type: the plastic type that was on the earliest units tended to go bad after a few months' use.
I don't know what 1265's in good condition typically go for, but wild guess I'd say $200-250. You can probably get better answers on the Fisher forum.
You didn't say which BH model you have. The lowest price tag units air test about 5-7 inches on coins, whereas the top-of-the-line Platinum and (discontinued) Time Ranger typically air test about 10-11 inches.
If you're in the market for a new high performance detector, we've got those in the Teknetics and Fisher product lines.
--Dave J.