Following on from having bought the thing, I can now talk about what it's like to actually use.
For some reason, paying £2 a day to use it when I have a perfectly good broadband at home did not appeal. But as I'm away for six days from tomorrow, and at various other days in August, I decided to set up the £15 for 30 days option.
According to the documentation and the awful website, the only way to do that is to send a (free) text via the USB stick and that can only be done via the Windows "web'n'walk manager" software (documentation) or – possibly – the Mac equivalent too (site).
Step one: put some credit on it. There's an 'etop-up' card which can be used at thousands of shops etc, but it's Sunday and I am not dressed yet. So it's off to the T-Mobile site to pay by card.
To do that, you need to register. Tap tap tap… password… wants a digit. Use a different password. Tap tap tap… 'We have sent you a text with the PIN you will need to access..'
OK, it has to be onto step two before I can top-up.
Step two: stick the USB stick into the PC running Windows. It is detected as a USB data stick (you can put a MicroSD card in it for data storage) and a CD-ROM (there's a read-only data partition with the Windows software). Install the software. It's neither signed nor certified, so say ok, install it anyway. Reboot, as requested.
It can't find the modem. From the look of it, although it has a 64 bit version of the driver when it says "# Operating system: 2000sp4, XP SP2, Vista (32 and 64-bit versions)", the 64 bit qualifier only applies to Vista, not XP.
OK, I have 32 bit XP on the old laptop, let's try it on that. The first problem is that its USB ports are rather wobbly (it was bought s/h and one of the two has always been ishy) and it turns out that it won't work plugged into a USB hub PC card (not enough current, probably). After some putting some support underneath the USB stick, it's recognised and the software is installed. Reboot.
Oooh, it's found the stick! A few seconds later, the text arrives.
OK, off to the T-Mobile site and use the PIN to confirm it's me. Top-up by £15.
I get more texts, including one telling me as a special bonus for that, I have been given two whole free texts.. but only to T-Mobile customers. Gosh.
Send the necessary "30 day" text. A reply tells me "You are not eligible for that reward". Hmm, is that talking about that wonderful bonus (according to the site, people with just mobile broadband aren't allowed to get bonuses)?
Wait the necessary half hour for the confirmation text saying the 30 day access has been set up.
Get a couple more texts, including one saying that topping up with £10 or more online results in an extra £2 credit. That's more like it. Check credit… £15.
No confirmation text arrives. Try again. Again, "You are not eligible for that reward". Nothing like a helpful error message, but it does confirm that it's talking about the 30 day package.
OK, ring them. Annoyingly the alternative to the 0845 number is an 07 mobile one, so while the alternative is probably free for people with mobile 'any network' packages, it isn't for me.
It turns out that the SIM, sealed in with the USB stick modem, is a phone SIM, not a mobile broadband one. Incredible. This is sorted out on the phone and it turns out that they can set up the 7 or 30 day packages as well – no need to dig out a Windows PC in future.
The confirmation text arrives…