Haven't seen these units in the wild, but here's what I can glean from the website.
Those units appear to be using the 900 MHz ISM band, which is typically used by low power, intermittant transmitters (such as Zigbee devices). This means that no frequency coordination is required or possible, but also introduces the possibility of random, difficult to locate interference sources. There also appears to be a 16 transmitter limit before there start to be compromises to audio quality.
As Sacom isn't a capsule manufacturer, there are some questions as to how good the microphone capsules they offer are (looks like they offer Audix OM3 and OM5 capsules in addition to their own), and what third-party capsules can be fitted. Bodypacks use TA4F, but it isn't clear what pinout they use (there are at least 2 incompatible pinouts).
There doesn't appear to be any Dante compatibility in the system, which may or may not be an issue depending on your expansion plans. Transmitter battery life is noted at 8 hours on the lowest power setting, so will likely be shorter than that in typical use. I didn't see charge times listed.
