I have been a CJ fan for years and currently own 2 models - a premier 14 and ET5 which you inquired about. The ET5 is airy, detailed, throws a wide clear soundstage with a very smooth revealing top end. I have used it with the stock EH and Philips tubes which CJ supplies. I prefer the EH out of the 2 and actually have a NOS semiens that I have not tried yet.
I like both units and am actually using my premier 14 with mullards currently. For me, it matches better with my Thiels and gives a slightly warmer, richer presentation. I have not heard the other models you mentioned. I like switching them in and out on occasion but may part with the ET5 one day as I prefer the classic CJ sound. You can’t go wrong with CJ preamps.
I like both units and am actually using my premier 14 with mullards currently. For me, it matches better with my Thiels and gives a slightly warmer, richer presentation. I have not heard the other models you mentioned. I like switching them in and out on occasion but may part with the ET5 one day as I prefer the classic CJ sound. You can’t go wrong with CJ preamps.