Roger, first of all, congratulations on the EX3. It’s a great camera that shoots great quality video and I know you’re going to love it!!
I have a JVC HM-750 that also records in MP4 format.
Whether I use the Sony XDCAM EX ClipBrowser (this is the utility correct?) depends on what I’m shooting.
If it’s a series of short segments, then I’ll use Explorer to search the card for MP4 files and drag them directly into the Media pool.
If it’s a long form project (and most of what I do is), then I will use the utility to re-wrap (that’s all it’s doing, not converting) to MXF format.
The reason for this is that, because they’re FAT-32, the cards have a 4 GB. segment limit.
If I don’t use the utility on, for example, a 2 hr. continuous shoot, I have several 4 GB. clips which I have to manually tie together.
Using the utility automatically joins them into one long continuous segment (great for shooting plays which is what I did last night).