I've had my DVP for about 2 weeks (suspect I received a "new" "returned" phone however). Performance of the phone is back to normal after the update.
I was ecstatic when I returned home last night and secure-Wifi was screaming fast! AND there were no lockups!... at least for a while. I opened up a number of apps that I had problems with crashing on Wifi and a majority we perfect. Only T-mobile's lame streaming TV app locked up the device completely... it's getting deleted anyway.
This morning, however I woke up to find the device had locked up when my alarm didn't go off. There appears to still be an issue with syncing over Wifi (the phone was plugged in to charge).
Despite these two crashes, I couldn't be happier with the latest update to .7392.
Hoping the rumored firmware from Dell in about a week will take care of the remaining Wifi issues.