The only stuff I'm missing out on are the machines, primarily the Block Breaker, and I have Minefactory Reloaded for that, with the added advantage of actually requiring fuel rather than running off magic.
E: that's not to say it's a bad mod, Redpower is amazing. I just don't like my game freezing up every 4 minutes while a new volcano is generated, right on top of the grove of diamond trees I was tracking towards