Which one of the two would you recommend, as my computer is too low-end to support P5?

What do you consider "low-end"? I'm running P5 on a 400Mhz Pentium2, with 128MB RAM, and Win98. THAT is low-end ;P Runs ok for me, though large models and scenes react slowly (like the MilDragon) There's not going to be a lot of difference between the P4s and P5 speed wise. I'd say go for P5 anyway, but try the P4PP demo first. If you can run that you can run P5, though the dynamic stuff may be tough (I haven't bothered to try those on my computer, it'd crash most likely.)

I strongly recommend ppp, I've had p5 and don't think it's up to much hope they do better with p6.

I've run my poser on a 150 mgz 486dx running win 98 and 96 megs of ram. Slower than molasses in january, but it run. If you want all the little quirks of poser go for p5, but if you just want it for creating and exporting to other programs, pro pack is the best. (I run both).

I still user Poser Pro for most of my renders, check out my gallery sometime.

I would say PPP if for no other reason than to get rid of that very annoying problem with geometry rsr's where the file refuses to open so you have to delete the rsr. PPP doen't use rsr's so it doesn't have that problem.

P5 doesn't use rsr's either, it uses png thumbnails.

Further advantages of Pro Pack over P4:

2D motion blur
additional file-format support
a few animated material options
the Setup Room for rigging your own figures
file compression
Python scripting

and for ppp:
lower hardware requirements.
stable reliable release ( 5 may be there now have no idea )
most people here have it and can help with questions.

for p5:
bleeding edge ( latest and greatest waste of funds as per societie's current practice )
most freebies and products are now only in p5 format.

Actually the most supported version is P4, P5 support is slowly gaining ground, but still no official support from DAZ. The only reason to get P5 is for the material editor which has a learning curve but is much more powerful and also for the rendering engine which is of better quality. But a better rendering engine usually eats up more ram and cpu. I would go with ProPack, no more bum files, and no more rsr thumbnails.

If you want to do any animation, definitely pro pack because of python support. I can't live without python any more, so can't live without pro pack. Many other advantages as discussed in earlier posts. good luck...

IIRC P5 supports Python too. I know there's a Python script option under the File menu.