We've just got a WPS500X kit, and yes, it's great
but, you'll still need to create lots of adaptors for fuel rails, hydraulic circuits etc ...
even with several kits of manual gauges (which all seem to use unique quick release fittings - within the same brand) means custom adaptors to fit the WPS500, so buying the kit is only the start. We have lots of engines running as 2 separate banks, and having 2 of everything to see live running data has been key for 20 years, sadly can't run to 2 WPS500's so need to keep the ability to run the gauges side by side for comparatives (and sense check).
We avoided most engineering (no lathe in house) costs, by buying spare parts for the kits to get adaptors to create 2 way conversion, so we can plug anything onto a Foster2, and can plug the Foster2 onto any kit, that way we can swing back and forwards without undoing everything, just quick release. The savings using bought "spare parts" has been considerable. Sealey are very good at this, others a bit hit and miss.
We try and start using the Pico Kit or our own T adaptors (for low pressure we've standardised on the Foster2), reducing extra pipes (most fuel pressure testers use long pipes, that allow pulse deadening (they are not braided), which is key for detailed analysis of the capture.
We have ordered a load of male and female Foster2 from the USA, with various male/female/push fit connections, as apart from the one Pico sell, they are impossible to obtain in the UK or Europe. If anyone is stuck please let me know, as we have spares!
Not thought about USB for powering sensors, we've used car voltage and 5v boards to provide stable power, but that's a nifty idea, and pretty easy provided the power demand is kept under review ... anyway cheap USB power meters are only a few £, so should be easy to keep track of it.