I inadvertently came across this discussion and although it's old thought I should comment as WAN Emulation technology has changed since 2013. You've already seen from your own experiences that there are limitations with the 'free' tools and they also don't always provide the accuracy or realism required for enterprise application and data transmission testing.
iTrinegy have partnered with VMware since 2014 and we released our first VMware Certified Network Emulator Virtual Appliance in 2015. It enables you to create many types of real-world networks such as WANs, Satellite, Mobile, WiFi and DSL in an ESXi environment. There's further information on the VMware Solution Exchange Alternatively we're running a webinar in early June, details here
Hope this helps even though it's five years later :-)