The PE on the Tamiya Panzer IV is made by Eduard and I don't care for it. It's too uniform and lackless of detail. The kit is overpriced also.
The Tamiya Jagdpanzer IV, I believe is out of production. It came with a long barrel. I built an Nichimo one many a moon ago. I would lean to the Dragon version if you can find it, better value for the buck. You get PE, barrel and indy tracks as a bonus.
Sorry, did you mean Jagdpanther? I hear Tamiya's is a dream to put together, but has no indy tracks. Like you said the Dragon early Jagdpanther comes with the before mentioned extras. I'd say tough call.