Jimbo,
This is not fair comparison because original HT automation ends at three time based profiles.
TC4 + HTC + Artisan or Roastlogger will give you full control of your roast. You can save every roast, and later on replay it. There is a learning curve, of course, but I can assure you that you will be able to achieve perfect curve overlap over the template roast. I was even roasting 60g for cupping. You controll fan and heat with 1% increments, although fan control is not as precise.
Automation is based on ingenious setup that I first saw in Roastlogger:
Up to the first crack triggers are fired based on BT
After FC triggers are fired based on time from the FC.
As I said previously, if you can go without wasting money on HT upgrade, go for the TC4 + HTC. Do check with JimG first though. He is great guy, busy at times, but aren't we all.
Look up at Homeroaster forum. I read about some new product that use native USB communication, not serial port communication...