Hello, Voice of Experience here,
Handy to have but dangerous without a splash guard. For all you lucky enough to have one of these little jewels, DO NOT test injectors without proper protection.
Up around the pressures where they operate; injectors will easily fire a load of fuel into yer tender young body. The first sensation (aside from the pain) will be the undeniable taste of diesel fuel in your mouth... and then the day gets worse from there.
The temptation seems to be to reach in and wipe off the tip of an injector that's not spraying right, and close to a pressurized injector tip is definately one of the worst places to be.