actually I do think Hatebreeder is more technical.
it's not about the speed, or how many notes you can play per second. and certainly not about the difficulty of the riffs.
I mean, I can play some parts of Bed of Razors as well, and I am a very bad guitar player.
but anyway, Bed of Razors itself has some amazing moments, like the dissonant part right at the beginning, which is easy to play but is so brilliant!
and also the very dark moment of Children of Bodom... so what I mean is: in terms of composition, I think Hatebreeder kicks some serious ass.
sure, the production of FTR is much better, and they play fast as hell, and it sounds more like classic, old-school metal than Hatebreeder. but here is my piece of advice for the newbie here:
Children of Bodom is not a question of quality. all their albums kick ass furiously. it's rather a question of taste. go to your local heavy metal store and give the CDs a listen before you buy. but get yourself some money first, you may end up buying the three of them.