I guess the 1/4 was first, then the xlr. I did some research and found they did change some of the circuitry, so which ones better, or need I not be concerned?
As you found out, the newer 441s had improved RF filtering. There might be similar evolutionary improvements in the 201.
Since your insert points (on the console) are unbalanced anyway, plugging regular TS plugs into the TRS jacks is electrically equivalent to shorting pin 1 to 3 on an XLR, which solved your RF problems on the other units.
I guess the 1/4 was first, then the xlr. I did some research and found they did change some of the circuitry, so which ones better, or need I not be concerned?