They are accurately scaled and as such they are incompatible with most of the oversize N scale knuckle couplers on the market today. You have to make a complete move to N-Possibles.
I believe Andrew said somewhere along the line that his are somewhat compatible with MTL TSC, another near-scale knuckle. Not fully operationally, of course, but you can apparently run a train with a mix of the two.
Personally, I really like the TSC for their appearance and no-slinky operation, but they can be stubborn to kiss-couple if not perfectly aligned, and uncoupling requires a dental pick. Also, the lack of conversions is a serious hindrance; I don't have the time to hack on every not-a-boxcar in the fleet with molded-on "1015-compatible" boxes.
I'm looking forward to the N-Possible and may well jump ship if it's everything we've heard and seen so far.
