AD524 vs. AD624?


I am designing an op amp circuit and would like to use either the AD524 (cheaper, available in surface mount package) or the AD624 ("newer" part number, but more expensive, not available in surface mount package).

Since both op amps seem to have relatively the same specs, I don't understand why the AD624 (the assumed newer part/upgrade to the AD524) isn't available in a surface mount package, or around the same price as the AD524.  I'm also greatly concerned because the datasheet for the AD624 was last updated in 1999!  (Whereas the AD524 was updated in 2007.)

I'm looking to choose the op amp that will be around for the longest amount of time.  With a date stamp of 1999, the AD624 concerns me.

Has anyone else run into this conundrum before?  Thanks!