Hi Woody,
This is a matter of personal choice, I prefer to use PP3.7 and use PD5 Premium for advanced editing, I seem to have less problems with PP 3.7
If you upgrade to PP3.7 you can still use PD4 for advanced editing, I believe that if you purchase the full vesion of PP3.7 ( not just upgading ) PD5 Express comes bundled with it.
It comes down to, how much control you want over the entire authoring process.
Regards
Intel i7 930, 16GB ram, Radeon HD 5770 1Gb,Ver. 14.12 Win7 64 bit
Intel i7 7700 HQ, 16 GB ram Nvidia GTX 1050Ti 4GB dual drives 1 TB SSD + 1 TB HDD Win 10
PDtoots