While the part can do 24MHz (on your bench) would you depend on it at altitude and temperature?

If it's just a project widget what the heck, try the 22.118MHz, however, i have found that serial data exchange can be quite efficiently dealt with at much reduced xtal rates. It really depends upon what you must do in response to the exchange.

We have a device that host's a 19.2 TxR, 14.4 Modem, and 19.2 terminal port (ignoring the 20X2 LCD) that has plenty of free board for processing. It's based upon a DS320 @ 11.0592MHz. Our free-board results from fact that the TxR is polled and buffered, the terminal interupt is for a human interface (slow), and the modem exchanges packet data (simplex).

regards,
p