The quality of a signal isn't directly related to the connectors or the cables used. A balanced audio signal can have lower noise than an unbalanced signal in the same environment, because the receiving electronics can be configured to reject certain kinds of noise (called common mode noise) from a balanced signal that can't be rejected from an unbalanced signal.
XLR cables have three conductors, which means they can carry balanced audio signals. Balanced audio signals can also be sent over 1/4" TRS cables, since those also have three conductors. 1/4" TS cables have only two conductors, so they cannot carry balanced audio.
The quality of a balanced signal is essentially the same between XLR and 1/4" TRS connectors. TRS connectors are small in diameter so they can be passed through smaller spaces and they take up less panel space. 1/4" TRS jacks can also be normalled and TRS connectors and jacks are usually less expensive than XLR connectors. For those reasons, TRS jacks are used for patch panels and many kinds of line-level signals.
XLR connectors usually lock when connected, and since XLR cables are made with one male and one female connector, they can be connected end-to-end to make arbitrarily long cable runs. XLR connectors also have the pins arranged to connect the ground first, and each contact only connects to the correct line. With TRS cables, the tip and ring usually briefly touch the sleeve and ring connectors when plugged in. This means that XLR cables are much safer for carrying phantom power without accidentally shorting it. For all of those reasons, XLR connectors are preferred for all microphone connections, where the low impedance can carry over long distance and phantom power is more often used.
It is possible to convert an unbalanced signal to a balanced signal using a DI box (DI stands for "direct injection"). This is a good idea when the source of the unbalanced audio is a long distance from the destination balanced input, and/or the input is XLR and the output is 1/4" TS, and/or there is a ground loop between the source and the destination input.
The linked wireless system doesn't just have an XLR output from the receiver, it also has a balanced audio output (you can see this in the specifications section). As it is a microphone system, usually it will be plugged into a preamp or recorder that has XLR inputs, so the XLR connector is the better choice for carrying the balanced output audio over a 1/4" TRS connector.