The F18 isnt that much newer of a design, a 20 year old from 1985, just lighter and cheaper...
Although, I must admit, from a maintenance standpoint, I hear it is no contest. I don't know the exact numbers, but it is something like four times as many man hours for each flight hour to keep the Tomcat in the air (seem to remember 20 hrs. vs. 5 hrs for the Tomcat and Hornet respectively.)
Nearly 10 year difference in age. First F/A-18 flight in November of '78. Hornets achieved fleet IOC with VMFA-314 in 1983. F-14 first flew in December of '70. Tomcat fleet IOC in '73.