I've been trying to pinpoint a price difference but it's too difficult to observe as they are always changing.
Is there a general rule of thumb?
My own rules of thumb on whole shares only -
PTs are worth a little less than directs due to increased counter-party risk.
Burnside's are worth a little more than DeaDTerra's due to better feature set, in particular the ability to convert to direct.
PTs on BTCTC are worth a little more than PTs on BitFunder due to reduced lag (3 vs 6 confirmations, and I reckon more than 1 investor has been surprised and confused by the weex requirement).
However, increased lag on BitFunder causes their PTs to be priced slightly differently.
PTs on BitFunder are worth a little less due to the amateurish-looking-ness of both BitFunder and WeExchange, and the perception that one or both may be easily exploited.
Prices on Bitfunder for DeadTerra's passthrough are lower because DeadTerra has thousands of shares he is trying to sell for one of his investment groups. That sell side pressure leads to large spreads between BTCT and Bitfunder at times. Also the fees on Bitfunder are over 3x the fees at BTCT so it is undesirable to hold shares on Bitfunder.
Don't try to be clever and buy up shares on Bitfunder and try to transfer them. I bought well over the 250 share minimum and requested a transfer to my direct account. DeadTerra never acknowledged the request and after a month I got tired of chasing him all over the boards here and just sold, eating Bitfunder's outrageous fees.
