I've played my 4003 using ROS through my PJB M500 head and 8-T/16-B cabs, and it sounds incredible.
I've run it in a few different configurations, & always for recording or home use - never live (I only play my Spectors live these days).
ROS/PJB setups I've experimented with include;
PJB for the highs, SWR Headlite & 1 x 15" for the lows. (great!)
PJB for the lows, SWR Baby Blue II combo for the highs. (even better!)
And my favorite - PJB for the lows, Hughes & Kettner Tubemeister guitar amp, dirty channel, through H&K 1 x 12" cab for the treble. (absolutely rocks
The Phil Jones cabs have fantastic highs and attack due to the quick response of the 5" drivers, but IMHO, to properly reproduce the lows (and move enough air to feel
the lows, especially in a live setting), you need a PJB cab with a minimum of 12 to 16 of the 5" drivers.