Go with the Black Knight because the plinth is important. The lead loaded platter also improves the sound image and clarity. I sold my HW19 MK III plinth and built me a cocobolo plinth with lead loaded. The sound improvement is great. You can use your current platter and bearing on your homemade plinth. I use Black Knight platter and bearing on my home made plinth.
VPI HW19-IV or Aires Black Knight
My record collection is very large. I have a HW19 Jr. with Audioquest PT6 arm that I have been happy with for the past 7 years, but now want to upgrade. I've read that the HW19-IV is a very good turntable, and I can upgrade to it and get the JMW 9 arm for a total of about $2000.00. On the other hand, I can get the Black Knight for $2,800 including the same arm and can sell my existing turntable and arm for 3 or 4 hundred dollars, meaning that it will only involve an additional outlay of about 4 ot 5 hundred dollars to buy the Black Knight. Which is the better route to go?