We used the 120VDC version on a manned submersible "Triton 1000" from US Submarines.
2 were rotating the wrong way (control wiring mixup) from the factory, but they fixed that easily.
The 4 thrusters have been great, with no problems. US Submarines has since used them again on their next build, and appear to be buying more for a new sub.
Going to the 300VDC version would definitely give you more power.
They were quite small, yet powerful for their size.
Good for a small electric vehicle. They are cheaper than other DC brushless thrusters, yet as much as a higher HP hydraulic thruster.
Always trade-offs. Do you want more power, or all electric?