TBII's are getting rarer and rarer, and you cycle stuff around quite frequently, as we all know...
Old Jazz' are not as scarce but are probably more desirable, overall, so demand higher prices...
As instruments, they are chalk-and-cheese so it is an instrument in your hands and the feel it gives you...
Do you need a Jazz right now, and how soon will you regret letting the TB go...?
That's your usual conundrum...