I know this is a late bug report now that there is an update, but were seeing an odd behavior with this version. (I'll report if I still see it in today's update.)
Basically, my PC is left on for 24/7, and UMS is running the entire time.
My PS3 is turned on and off several times a day, and occasionally UMS would not show up as an available server. UMS still looks like its connected to the ps3 since it found it at startup. Sometimes having he ps3 search for servers again would pp it up, but most times I had to stop and restart UMS.
Not really a big deal, since it was an easy work around, but it might be something to keep an eye on for stability's sake.