Dell took its sweet time updating the super-slim Venue 8 tablet to Android 5.0. It finally got this done back in early May, though this was after blowing several previous release dates. To make up for it, Dell just pushed Android 5.1 to this device. I'm a little surprised Dell hasn't moved on yet.
Since Dell has wisely decided not to go crazy modifying Android, the features you can expect are roughly the same as every other Android 5.1 device including better heads-up notifications and enhanced quick settings. Dell has also made some tweaks to the depth sensing camera processing, which has always seemed pretty broken to me. Then there are the usual bug fixes and miscellaneous enhancements.
The update is available over the air from the update menu right now. I've been having trouble getting the download to complete, but our tipster successfully completed his update.