Was running WHS V1 for about 2 years then upgraded to Windows Home Server 2011 for close to a year now. No issues with data integrity, accessing data, or restoring backups. The only issue I noted was after the server was shut down by the ACP battery backup, the server did not start up when power came back on. Not sure if that is a WHS issue or the battery backup issue. Haven't had time to look into it.
There are only a few addins, the most notable is Stablebit Drivepool. The others are Advanced Admin Console 2011, AWIECO DriveInfo, and Home Server SMART 2013. All these addins have performed flawlessly.
I am especially pleased with Drivepool, as it just does what it is supposed to with no fuss and gives me the data duplication that is so important to me for family videos and photos (and I have a lot going back to 1999 when my daughter was born).
There are seven computers that are backed up on the server, and I have restored from at least 3 of the backups with no issues what so ever. All are Win 7 Home Professional.
The box itself is a homebuilt machine with highlights in my sig below. It too has performed flawlessly. Important info is the data drives typically run 92 to 98* F, and the system backup disk typically runs 98 to 111 F, but that is because if its location that makes cooling difficult.
This system is so well behaved, it has been months since I signed on to the Dashboard. The Alerts tell me everything I need to know, and the daily email keeps me posted. Such a pleasure over WHS v1 that constantly needed restarting. It would just stop responding, But luckily for me, it never lost any data.
Just thought I would share my experience. If anyone still is running WHS V1, and is thinking about upgrading to WHS 11, I say go for it, regardless if the newer software is out. WHS 11 is stable as the Rock of Gibraltar.