@newbie,
Don’t know about copter simulations, but I can tell you about Spektrum products.
As you have noted, Spektrum sells both transmitters and transmitters with receivers. Transmitter only is for people who already have Spektrum transmitters and receivers and just want to add an additional or upgrade to a different transmitter. The Transmitter/Receiver packages are just what they say they are, a complete package for those who do not have a matching Spektrum receiver. Some even include servos.
Regards,
TCIII GM
@ckashy,
If you are going to be flying a multicopter, I would recommend a minimum of a DX8 and a DX9 if you can pony up the extra cash.
I have Spektrum DX5 through DX8 transmitters and mainly use the DX7 for my rovers/boats and the DX8 for my Anaconda airplane.
Regards,
TCIII GM