No probs. I am the other way around, I am 95% ARCserve, about 2% Legato, 2% Tivoli and 1% Veritas.
Once you're used to one system it's really quite hard to convert
When I last looked at Veritas I found the whole scheduling to be quite foreign compared to what I am used to in ARCserve, but I have talked to Veritas users who have the same opinion about ARCserve!
Probably the biggest architectural difference between Backup Exec for Windows and ARCserve for Windows is how they interface with the hardware.
BE relies on either Windows drivers or Veritas provided Windows drivers to interface with the hardware, whereas with ARCserve, the device support is identified from the SCSI Inquiry string and support provided by ARCserve's own tape engine, which uses SCSI pass through to communicate with the attached devices.
Both methods have their pro's and con's. Because ARCserve uses native commands so to speak, it can be faster. However if there is a problem working with a specific device it can be more complex to debug, especially if a device firmware issue maybe suspected. From my understanding Veritas just use the device driver as a proxy and then 'blame' the device driver if it doesn't work.... but maybe I'm a little biased ;-)
If there is something specific you are looking for more detail on, ask away and I may be able to dig something out or write something up.