The latter was what I was having trouble with periodically until it got to the point where it wouldn't keep the heaters on long enough to get to temp, much less run a print.  I've got a 2 week old SD2 Pro / Windows 7 PC.  After changing the cable did nothing, I started digging around in my settings and found that the baud rate in RH under Printer Settings was set to 115200 while the setting on my computer for the com port was 9600.  Once I set the com port to 115200 all my problems went away.

HTH

It is irritating that I can't trust the machine to run a job w/o babysitting it.  Don't want a hours long job to freeze with hot extruder sitting in the middle of a blob of plastic.

Understand need for good USB cable.  I've tried a couple of different ones and will investigate others to see if it helps.

*** What is the best procedure for debugging potential problems with Repetier-Host and/or the Solidoodle firmware?

Is there a way to force a reconnect on the USB serial connection?  Are there any alternative drivers? I've built USB firmware on microcontrollers and am familiar with how much error checking and correction is needed.  I'm not convinced the one supplied by Solidoodle (Teensy/PRJC) is particularly robust.

I am mostly printing PLA on a clean piece of glass clipped onto the bed.  Z-Stop and bed adjusted so the surface of the glass is very close to flat at Z=0.  Extruder at 185 and bed at 55 have been working well, no need for hairspray except for a couple of objects with small bases.  Results with ABS ok as well.  I bought both types from SainSmart and have had not issues with quality.