As mentioned before, we hired a wifi2go device for our holiday, which sadly finished on Saturday
I had booked it before we left, using the discount code at the beginning of this thread. I also booked an external aerial as the villa we were staying at was between PP and Pollensa, so didn't know what the coverage would be like. However, using the discount code meant that even with the aerial, it still cost less than the listed price on the website for just the wifi2go device itself.
Collection was faultless - you just go to the TUI desk after leaving the baggage collection area, and they had it ready for me in a bag, including the aerial and a mains charger.
The device itself is the size of a very small mobile phone - certainly smaller than an iPhone, and very thin.
The battery lasted for probably about 6 or 7 hours usage between charges.
The device does run extremely hot when being used, but that's not really a problem.
As it turned out, we didn't actually need the external aerial - reception was fine both outdoors and indoors without it, but as I said, with the discount code it meant that in effect I hadn't had to pay for the aerial anyway, so I wasn't too bothered.
The only thing I would say is that it would be nice to have come sort of usage monitor. I went for the basic device, which gave 1Gb/week. Daughter and her boyfriend were both instructed to keep browsing to the minimum, and not to start downloading films (!), but I would like to have been able to keep an eye on how much we were using.
I emailed wifi2go on the second day to ask if there is any way to monitor usage, and I almost immediately received a reply saying that there isn't, but that they would let me know how much had been used. A few hours later, I received a second email telling me my current usage - very efficient.
I then emailed them again towards the end of the first week to ask for another update, and again they very quickly responded - however, I was surprised to see that at that point, we had used almost the entire 2Gb allowance, with still over a week to go.
However, they then went on to say that they had added a complementary 1Gb, which was an extremely kind gesture.
At that point, my daughter and her boyfriend we going home, so it was just 2 of us using it for the second week, and we obviously didn't go over the limit for the second week, so I suspect that daughter had ignored my advice and had been streaming things to use up the allowance!
Return of the device was even easier than collection - just dropped it off at the TUI desk in departures, and didn't even have to sign anything.
So, to sum up, I would highly recommend one of these if you need wifi in Mallorca - very good value, and extremely good customer service.