The YJ P51 is a great tool, it has thermistor temp probes that are wired, vacuum gauge is seperate from the manifold and really great, reads right with my BluVac Pro. I have nothing bad to say of the YJ, but it's not up to the FP 380/480.
I use the 380, with JL wireless temp probes and psychrometers, and it is THE best manifold I've used and I use to be a AK900 user. These blow it out of the water. To have EVERYTHIING right on the screen in front of you in real time is fantastic. It even reads the FP scale so yo can automatically keep track of how much refer you've put in. Logging is fantastic and I normally use the JL app to calculate TEET to see delta T over the coil. I won't be using anything else.
For history, I've used AK900, earlier SMAN, Testos, and YJ P51, nothing compares.