Why does Bitcoin-QT not seem to be catching up on my Mac? I've had Bitcoin-QT running for about six total hours, and the rate at which it's catching up is glacial at best. It takes about an hour to advance a week, which would make the process take about 4 days to complete. It didn't take nearly this long on my PC; I started and finished the process while my Mac was still running. I'm running Bitcoin-Qt v.0.10.1 64-bit on a 2011 MBP, 8 GB of RAM, on 10.10.4. Is this normal, or is there something wrong?
Sadly Bitcoin-Qt's (and bitcoind's) default DB cache size is very small for systems like yours.

You should definitively add -dbcache=4000 (use 4GB of RAM for UTXO-set-database [etc.] cache).
This should speedup your sync significant.