Here speedtests were made in Schlieren ZH near the railway station. Swisscom network with abo iOne XL on 4G+ network. Device in (syntetic fibre) backpack in the building. Download speed approx. 250 - 300 Mbit/s. Tested this several times to check the data. I used the additional SIM card that comes with the subscription. All this without external antenna. Only device with approx. 60% battery charge.
Important, this speed is only achieved with 5GhZ WLAN. In 2.4 Ghz (at least for me) it usually stops at 120-150 Mbit.

Tested on an iPhone Xs with the latest iOS version.

I have now bought it on a trial basis. If the speed doesn't work out, I will return it.
Thank God Digitec is at least customer-friendly.

No not yet

Without having tested it specifically, I have the feeling that the device is really very fast.
I can only recommend the device. But why it shuts off when the battery is full is beyond me.
But in the meantime I have got used to it.