Thanks again everyone. My action items/tests for tonight:
I'll test extrusion steps/mm for extruder (with no nozzle this time)
While i have nozzle off check for blockages
I'll test existing thermistor at room temp and w/ boiling water and report back.
I presume with this information we can adjust the config file?
We didn't talk about it, but i'll validate the extruder stepper motor wiring, making sure I don't have any phase wiring issues.
I'll report back after tests.
@Veti Is there a favored thermistor to buy, that has the data tables etc? Its only a few bucks so i'll get an order in to cover my bases.
@jens55 Thanks @jens55 . Concur on your approach. Getting first layer right is a future problem! Just didn't know if picture helped for any 'mystics' out there than can read the tea leaves in the print.
If it helps, here is a picture I took yesterday. On the brim (right word?) you can see it get thick/thin that seemed to correlate with the clicking/skipping.
@Veti I absolutely am not! 
I tried doing some searching on what thermistors they used on this, and all i could find was 'generic' information about them being 100k. New to this, but i did test that it read about 100k on my multi-meter, at about 25C.
Suggestions on steps to take / Tests to perform?
@jens55 I'll test tonight and report back. Thanks for the great instructions.
@jens55 Confirmed that i am using 1.75 mm filament. I think that 5mm/sec extrusion may be a red herring. Can i upload the actual generated gcode of the print so we can see speeds its using? Or is there a specific gcode line i can share to provide insight? Using same slic3r outputs/parameters i've always used as previous board was considered reprap as well.
@bricor Could i trouble you to share the heater line with the settings you used? I was leaning towards something along those lines, but couldn't find a Wanhao/Monoprice one to try.
@jens55 Thanks for suggestion re doing test w/o nozzle. Guess i fail in regards to generally accepted wisdom as I had it on! I'll redo that test tonight too. (Skipping at 5mm was indeed w/ nozzle on)
I'll take another look at the nozzle to see if its plugged. I'll report back on that later today. Not ruling anything out, but the print prior to board swap was fine...
I did tune steps/mm for filament, as extruding at 1mm/sec seemed to work w/o skipping so i could do a few tests measuring 100mm extrusion cycles.