I'll say one thing about the BitcoinXT QT client: it's surprisingly quick. Fourteen hours ago, my computer shut down due to overheating and I had to resynch all the qt wallets I was running after I had broken out the dust vacuum.
I had to delete the blocks & start again. Bitcoin QT, which I had started to synch off-and-on, was one of them. I've been running it continuously for only fourteen hours, starting with the genesis block,
and I'm almost half-way done. It looks like I'll be fully synched - from start to finish,
in less than 36 continuous hours.
Please remember, this is a
Bitcoin qt I'm talking about. I expected it to take weeks!