I'm a DCS noob myself so I'm gonna gove my opinion also from a noob perspective
so I bought the 2. the F-18 because it's a multirole you can do a lot of stuff with it so all round its the best bang for the buck at the time. and I also bought the F-14 simply because it's a F-14
at first, I feel like the F-14 would be a daunting task in trying to learn the aircraft but boy i was wrong. and here is why from a noob perspective.
For A2A ACM. lets say you manage to lock a plane, then you have to ID it using an IFF. the IFF on the F-18 comes in a symbol to let you know that whether is an enemy or a foe. now for me as a noob, this took me a couple of seconds to process the information whether or not I'm locking a friend or foe. in the F-14 I can just switch the VDI to TV. I can see what aircraft I'm locking at. also getting into the many ACM mode, the F-14 is much more straight forward. while in the F-18 if you want to go to Vertical scan Mode. you have to go to Boresight, then to Wide accusation, then Vertical scan(i might be wrong cause i'm still a noob)
BVR, you have to do it by yourself in the F-18. which mean slewing the TDC, interrogating a target and lock it up. while in the F-14, Jester would take care of that for you in TWS auto mode. any target that shows up will instantly get a TWS lock and prioritize it order so all you have to do is get inside the launch range and fire
and for the CAS F-18 wins hands down. you have a lot of weapon variation that you can use compare to F-14. however that' doesn't mean that you can't do a precision strike.
for campaign content, I played both "Hornet 1989" for the F-18 and "Caged the bear" for the F-14 that comes with the module. and I can say for sure that the F-14 campaign is a lot more noob friendly than the F-18 one
although I have to say. the flight characteristic is a bit difficult for the F-14. but because I have some previous experience from other sims. I know when I'm about to leave the flight enveloped.