Even though this book is still fairly new (opened in Oct, 2007). BetJoint has no outstanding complaints or processing issues levied against them at this time. In fact the only thing I found worth noting on this front was this.
As far as payout go:
On 2-12-08 SBR posters BAUS (x2), Uga Boga, and Jason reported prompt payment from BetJoint, which I did note in the payout report for February.
From what I've seen, they did. The player won the first 2 legs of a 3-teamer, hedged the third leg, and the book simply voided both wagers IN FULL, instead of voiding only the offending wager(s). See the linked thread for my analogy to voiding because the 3rd leg was bet on an obviously bad line. Even under BetJoint's hidden rule, they have no grounds to 1) not void the 3rd leg of the freeplay parlay (as well as the straight bet hedge) and 2) not pay it as a winning 2-teamer.