I haven't heard much about how the 300PF performs at close range, nothing bad at least.
Note that while the new lens focuses a little closer than its AFS predecessor (1.4m vs 1.45m), the it does not frame as tightly (magnification 1:4.1 vs 1:3.7). In other words the older lens gives slightly higher magnification with greater working distance. The difference is not huge but it might be important in some situations. For tripod shooting, I would favour older lens, but for hand-held use the 300PF with VR wins.
Also, the older version has a manual aperture ring, so it can easily work with extension rings like the PK-13 if you want to increase the magnification. The 300PF is all electronic so you would need a third party AFS extension tube. Not all IF lenses behave well on extension. The other route is to use a high quality closeup lens, like the Canon 77mm 500D.