(i) It's temperamental. The signal drops off about once a minute in the areas I've been using it in (Camden Street, Harcourt Street areas of Dublin)
(ii) The speed averages around 300k
(iii) It sometimes doesn't connect properly off the bat. I had continuous problems with getting it started one day and had to call technical support. Embarrassingly, it then worked fine.
(iv) It doesn't work with more modern laptops' card ports. I'm using it with a three year old Compaq laptop
(v) It has one very good feature -- no download cap. However, at 512k, one shouldn't be clocking up too much anyhow.
The 'Go' service costs €100 up front and €40 per month thereafter. Coverage is metropolitan Dublin only, with build-out planned for other cities.