I'm not a fan of propitiatory metrics in general, but as has already been said beware high CF sites. TF is more associated with quality, but keep in mind that neither of these mean ANYTHING really. They are only useful for searching for sites and narrowing them down, not judging. You'll need to manually look at their history on the waybackmachine and their link profile on whatever tool you prefer to really know anything. You COULD have a site with a high CF that you might THINK would mean it is spammy, but really just got one giant blast of something fairly harmless, or maybe it had a few forum sig links floating out these by guys who post a shit ton. So there are times when metrics lie, and those are usually the times when you can find a gem domain for cheap.
-ThopHayt