I bought a cheap Rolls pre strictly as a phantom power source to bench test mics. It was broken out of the box, with a severe low-frequency oscillation caused by the phantom power. I was able to fix it, but there is really no excuse for that.
Looking at the specs for that unit, the input impedance is kinda low at 600 ohms, most modern mixers will be over 1K. That may or may not be desirable, sometimes it's nice to have a low impedance as a sort of tone control, but in a basic mixer I don't know why that wouldn't be higher.
The phantom power is under spec, at 36V, which will make many condenser mics unhappy (although many electret condensers will be fine).