Over a decade ago, I had a Burr-Brown part that I'd used for some time, but there was no stock. The distributor showed a 2.5 YEAR lead time, but they could tell me the exact day the part would be manufactured. I got frantic, and found that TI made an equivalent part for 1/4th the cost, and reviewing the datasheet, it sure seemed compatible. I wasn't totally convinced until I actually put them in the circuit, and it worked fine.
Jon