I agree, located in Galway myself in good reception area have being testing various modems, o2 speeds are far better than 3 network which isnt suprising, but overall i think mobile broadband is just not able to cope with demand at peak time hours, fair enough o2 have done their homework regards setting up the modems properly to ease pressure on transmitter nodes, but service is downgraded when there is high demand from 5 - 9PM, and thats not good enough @40euro a month, One should get what they pay for, but with speeds varying from 30kbps to 2.5mbps think i'l be leaving mine back to the shop!
P.S. Installed FireFox the other day, much faster than internet explorer which is a help, but im afraid all the above still applies