I have now purchased 2 NIB Stern Machines. 1st was the Avengers LE, then Star Trek LE. At the time they shipped, both had rough software, which has improved since the initial release. On the hardware side, the Star Trek LE shipped with a much more stable and smooth hardware platform. May not seem like a big deal, but the Avengers has been a PITA since the day I bought it, with many calls to Stern to get fixes for the hardware, and it is still not right. Rough/buggy software may be annoying, but is better than a poorly designed playfield.
A previous response has it correct. As long as we pinheads continue to pay for these unfinished projects, we can continue to expect the same behavior from Stern.