Another vote for the Futaba 2.4GHz 3PM. I have 2 of them :).
Castle Neu 1520 on 6S LiPo Powered Gmaxx (Nitro Killer)
Predator with OS .21TM
Supermaxx with Mach .26
Revo with OS .18TZ
Kyosho ST-RR Conversion
Ofna CR with Tekin ESC/Motor (2)
i had the mx-3 too. Great radio just not 2.4 but since you dont care about that you are good to go. I only switched because i do a lot of meets and the frequency board was getting pretty full. for the 50 over budget the 3pm fasst is really great. I have a 3pk but the 3pm uses the same technology just not all the bells and whistles on the tx itself.
IMO
could get you by easily - mx-3
future proof and only 50 over budget - 3pm fasst
also dont forget the 3 easy pay from tower so it doesnt hurt your wallet all at once.