Well for me PBK has always been the slowest source from Europe. I did have some Zonda's wheels get lost in customs for a couple of months. They finally arrived in a totally trashed package. Sent pics online to PBK customer service and within a day or two they had refunded my purchase and told me to keep or trash the wheels.
I use this site a lot to track overseas packages.
Universal Parcel Tracking - Global Package Tracking
My last couple of orders from Merlin's have come via DHL but have been the usual super quick shipments I always get from Merlin.