I currently have three packages approaching two months in transit, where the usual transit time is between two and three weeks. I've also had some packages turn up much quicker than expected, from order to delivery in approximately seven days.
Registered items are being delivered as usual.
Most shipments are from eBay and AliExpress sellers, so it's impossible to be sure exactly what delivery method is being used, however one of the late deliveries is from Deal Extreme, and I've been buying from them for years.
Yes, I know there are seasonal performance issues with China Post, but this is the slowest packages have ever been delivered in over 15 years of online shopping. And don't get me started on iParcel... no longer using Amazon because of them.