I plan on doing a little benchmarking around this question, myself. But I thought it would be good to get some initial feedback from "the community". Has anyone out there done any analysis regarding the pros and cons of these two technologies? My thoughts: Opening and closing TCP/IP connections for web service calls is relatively expensive compared to persistent connections. Dealing with intermittent connection errors and state, etc... would be easier with a web service based framework. You don't see World of Warcraft using web services. One question that I can't seem to find much of answer for anywhere (even on here)... are the limits on the # of persistent connections a single network card can support, etc?