I have it - the middle one, its £7.50 a month for me as O2 mobile cust but its the £12.50 we have.
Had it about 2 months and to date no problems. No hanging or laggyness. Its easy to set up if you follow the cd, and diagnoses problems if you cant get online - its happened to me a few times but has always been down to little man playing with the router and breaking it lol
so yeay a big thumbs up from me especially for £7.50 when mum & dad pay £25 from virgin and ours is just as fast!