I remember they had severe performance problems early, maybe they have been fixed.
Not fixed yet, but it's fast enough to be usable (for certain values of "usable")
It took over 10 hours to synchronize with the blockchain, downloading from a bitcoind node on 127.0.0.1 on a storage setup that was not IO bound. It looked like it was only utilizing 2 out of 8 cores during the process. Now that it's caught up it takes about a minute to verify a block.