I use both for different purposes
CCC allows you to boot from your clone
TM does not
Both allow you to migrate your data
I use TM to go back (if needed) to get a file or a "state"
I use CCC in case of catastrophic failure of the HD
I have had occasion to use both and both function well
How do you set drives up to handle both?
2 partitions and how large above the original should you go?
I use Time Machine, CCC, and CrashPlan.
Here is my reasoning:
1. Time Machine can go back in time and get older copies of files, photos, etc.
2. Time Machine will be great for getting a new Mac setup the way I want it.
3. CCC copies are bootable, so that will reduce downtime in the event of a HDD failure.
4. CrashPlan to back up my movies, photos, music, important files, etc. Basically, I like to keep things on here that can't be easily replaced.
Much like you, I use Time Machine for convenience, CCC for migrating drives and Crashplan for off site backup. I don't back up my movies off site. I can always simply rip them again. I keep the original DVDs down in the basement next to the 78 rpm records, 8 tracks and buggy whips.