Which: VPI HW19 Jr. or III vs. REGA P3 and P25

I would recommend the P25 over the VPI, simply because it just sounds more musical, especially in the area of PRaT.

For some very interesting insight into Tonearms read this thread. Good luck to you on your adventure.
Strange tonearm tweak Long

I would skip over the P3. The price scale reflects performence in this case. The P25 may sound quicker than the VPI, but the VPI can be upgraded and/or modified. The P25 does not offer an upgrade path. I have the VPI and like it. Especially good value used. Im thinking of trying a cheap mod to tighten up the bass. Dont get the wrong idea, at this price point the bass is excellent.
Set and forget? Rega P25. Set and forget with upgrade option? VPI.
I would look at Origin Live if you buy the tonearm seperately. The modified 250 is a great value that has spawned many copies.

Rega and VPI both make fine 'tables. I would recommend the VPI because of the upgrade path, which the Rega doesn't have. However, if you are not into 'tweaking', the Rega is an easier setup. The Rega is much more of a 'plug and play' type. Only you can decide whether you want to tweak and upograde, or you want to set it and forget it.

Regards,
John

The VPI Scout is better than all you have listed.