I'm your man here!!
I'm a pro user of John East's pre-amps and I'm now having a custom bass built buy Alan. I tried a couple of the new jazz basses at the London bass show with pleasing results.
To start they look.....great.
The playing 'feel' was first rate! Well balanced and not heavy (but not too light for me as I like a bit of weight on a bass...).
Fast necks, nice string spacing, 24 frets with good upper register access (woo hoo!). I'm well at home with the J and U-retro but was genuinely amazed with the new P-retro. Plenty of tone with fewer knobs (GAS attack!). Slap to Motown well covered.
Being more of a 5 string player, I was pleased with the 'B' and I think that they are 34' scale length! (Correct me if I'm wrong). The 4 string had the fat 'E' as well (Marcus Miller time!).
I had my pal Tom with me (a player/sound engineer) as an extra set of ears, and he had good comments about punch, tonal variations (good for my ego), but it's the bass he was talking about :-(
It's hard to re-invent the Jazz bass but this is a great take on a classic. I may have to shift my Jazz style 5 string for one!!