Not sure there is any way to know beforehand. Maybe ask the seller to open it and check for you? Some may be willing to do that, others may not, depending on the volume of business they do.
1) Haven't heard any complaints of that since those early few.
2) I still haven't heard anyone comparing the two. Seems the original EE unit was incredibly popular, then everyone sold theirs and moved on, because I don't know anyone who still uses theirs.
NuWave looks interesting (despite me not being a huge PS Audio fan), D2 is spectacular, Octave seems great too and somewhat similar to the D18, and BiFrost probably doesn't compete on the same level as those others.
The D2 is currently out of stock and despite mostly positive comments I'm under the impression that its might be on the cool side of neutral. No reports yet on the NuWave as there appear to be production delays. The Metrum is interesting but I've owned NOS DACs before and even though it doesn't have a typical NOS sound I'm still hesitant to go down that road again. On the other hand I'm in Canada so getting my hands on a D18 would be fast and with 30 day return policy.
The modded tube output on my EE DAC just died. I could probably find someone to fix it but at a cost.
I'm also tempted by the "warm yet detailed" sound of the D18 over the snappy, yet at times, unforgiving sound the EE.
On the other hand I don't want to spend $700 to achieve only marginal improvement(or less) over what the opamp output of the EE provides.