JX-3P is one of my favourite synths. I also have 2 Polysix, and yes different areas completely!! Polysix sounds gorgeous though, while 3P is very unique sounding and great for a variety of tasks - I use it all the time in my music.
Either are great buys for different reasons but to start with, a 3P is a great choice and more advanced.
I have had all the junos, the 60 is great, the alphas are sweet but NONE of them have brought me the great dual osc sound of the JX-3P (had the 8P too which is pretty poor by comparison to the older 3P), the Junos were always first to go before I ever considered letting the 3P go - you have a much more up-market synth in the 3P but hidden in sheeps clothing (and yes it has some flaws like LFO speed, no PWM, software envs) none of that matters to me and my music, the overall sound when you know how to program one is beautiful. You bought well.
V-SYNTH | POLYSIX x2
GONE: SH101/JD-800,990/JUNO 1,2,6,60/MKS70,50/JX3P,8P/D50,70/JV1080/AX80/SY77,85/DX7,IID,S,100 /TG77,500/TX802,81Z/AN1x/ MS2k/DW8000/PROPHECY/WAVESTATION/M1/CZ1/CRUMAR PERFORMER