These differentials have been proven to work but need a teardown and inspection and some new washers.
The axles are a tight fit but it can be fixed by honing them out a little after the bearings are pressed on. Some users have said that they fit better depending on how you clock the axle relative to the spline.
The other big problem is that the belleville washers in them crack and sometimes even arrive DOA. I am selling replacements for $16US or $17US to canada. Just send me a paypal for the money to rich_bryant_is(at)yahoo.com (replace the (at) with @ I am spam protecting myself a bit) and I will send them out ASAP.
See my description of the teardown here:
OBX Differential Teardown
Overall for ~$450 with the washers it isn't a bad deal compared to the $1300 quaife.
BTW I actually get the opposite impression about OBX. Their Helical diff is often considered one of their only good products!
-Rich