Being a user of both Futaba and Spektrum radios I can tell you this: In your case the DX3S will be just fine. It has all the features you could want for a short course truck (In fact I use my spektrum radio for my SC trucks too) and the receivers cost half as much as Futaba receivers. They are also a lot more durable and not voltage sensitive. Spektrum also has the model match system, so if you accidentally leave one truck turned on in the pits while you drive the other, it won't drive off your pit table. I see Futaba users do that all the time.

I use my 4pk for onroad racing where it is desirable to have a faster response time and a few more tweaks available that help out with the TC classes.