Interesting!
Without giving anything away.
No.3 which I disliked I kinda guessed right what that would be. It just sounded like there's a mid scooped to it to my ears. I personally would not want this one.
No. 1 - When it started and when from 1st to 2nd on the P bass my first thought was "sound like 1 has higher input impedance than 2" which I think it does - I enjoyed it on the Sandberg, and less so on the P. This was ok.
Number 2: Big sounding, colourful mids. This is a nice sounding preamp/DI. But I like this style of thing. I'ld use one.
Number 4: was not expecting to like this one. It's clean, with 1 seemed to have the widest freq range- has that balanced warm unhyped sound that is good unless you're going to go for a colour. Enjoyed it on the P bass, less so on the jazz - which is possibly the higher freq of the rounds.
(for reference, my dream sound is the old Warwick hellebore preamp, and the last 2-3 years the v2 Colourbox has been at the end of my pedalboard, so I like things with transformers in!)