"Better" depends on what your needs are. I'm a linux newbie, and no computer whiz by any stretch of the imagination and I use Mandrake. Mandrake is supposed to be one of the more user friendly distributions, so for me it is better than Slackware. Slackware is supposed to be the lean, mean, fighting machine of popular linux distributions. So, based on your question Mandrake might be better for you.
That is one of the beautiful things about linux. It's not one size fits all for the purpose of marketing product. It is personalized to meet your needs.