OK so I have played these, AND I have serviced them. Here's a quick, drive-by reply:
They don't s#ck.
And I expected them to, because they are so cheap, new.
But what I found was their regulation holds well, the horn was not riddled with the usual imprecisions of construction one finds with cheap Chinese horns: key play was minimal, the post screws moved in and out smoothly, key action was reasonably responsive.
Intonation was decent.
Tone was nothing to write about...it was a bit thin and bright; a Yama 23 ( a horn which I do NOT think sounds good, tonally) sounds a little better than a JP.
The strap eyelet is cheap...on two horns which had been owned only for a couple years by players who played them often, the eyelet was wearing thin. The pads are basically budget chinese pads but they had not failed on any of the horns, again after 2-3 years of player use. They weren't soft and fluffy, they were medium-ish, okay.
The body metal is ..OK..I mean it didn't strike me as chincy or alarmingly light. Two owners were kids in HS and college who used them in marching and stage bands and they got a lotta road time, and again, they weren't falling to pieces at all, nor riddled with dents.
The key casting quality is a bit meh....but the keys weren't 'soft' by any means.
Their blowing response wasn't bad at all.
So, for the $, for a new horn...if one insisted on a new horn.... and all you could buy with that money was a cheap new horn made in China - a JP wouldn't be a foolish choice, honestly. I might go so far as to say its probably more of a known quantity/quality than most budget, store branded horns.
My question would be...if your budget is limited, why not get a used horn of greater repute/longer track record instead ?
But again, it isn't the 'typical chinese budget horn'...which IS something.