I use an older 3PK and have had it now 4 yrs or so. It has capabilities I'll never use or even understand. I haven't moved to their FASST system due to cost (I have 13 rcs I'm running off the 3PK) and since I just bash, I would rather put the money for new radio plus 13-14 new rxs toward another rc or some hopups. I've never had probs on FM and can drive mine literally out of sight range wise. Don't see how could be better, just newer.
Its an impressive looking tx though, but for me, I'd have to find a deal like I did for my 3PK before I'd consider one. Think you'd need to be an elite racer to really benefit from 4PK's capabilities. Other txs will give you 95+% of same capabilities for a less $$s. If you want the best though, thats the best Futaba's got to offer currently and will be their flagship tx for several yrs to come.
I also have a 3PK and use it w/ 5 vehicles. I love mine...now that I understand it I agree w/ Duster, the 3PK is plenty of radio for just about anyone. Be prepared to spend some time reading, re-reading the instructions.
1. MBX-6 T8 1900KV, RX8 ON 4S
2. MBX-5T 1520, MMM ON 5S
3. MBX-5 ONROAD CONVERSION 1515, MMM ON 5S
4. MRX-3 ON ROAD CONVERSION 1512, MMM ON 6S
5. TEN T 2650 T8, MMP ON 3S
Personally, I'd get FASST module. I've read about some probs with the other. I think it makes sense to keep everything Futaba.
The manual is your friend, lol!! This is not a radio you can just pick up and use, you'll get nowhere fast. It takes a while, but the more you use it, the better you'll get to know it, understand it and like it.