I have also found the battery life to be less than desirable. I've noticed the radio flicks from 3g to H alot where as on my desire it would rarely switch to 3G and would remain a solid H. I believe this has something todo with the drain discussed.
H mode uses more battery, and uses limited resources on your providers phone tower (there's only a small number of H slots). Switching temporarily into H while you need high performance is the correct behaviour. If your phone stayed in H all the time the battery wouldn't last very long. The only change in behaviour you could do here to save battery is to disable HSDPA altogether at the cost of performance.