Jordan had never seen (or to my knowledge has yet to see) splunk at all. I don't know about Pete. Myself, I haven't used Splunk since trying a very early release once in the very first days of it.
Point being, Logstash doesn't call itself an "open source splunk". In fact I've considered adding an output to SplunkStorm to Logstash.
Do I think Logstash is better? Yep. Do I know people who swear by Splunk? Yep. Competition is healthy.