It's very easy to un root. The problem lies with locking the boot loader back. This is what voids the warranty. I have mine rooted because, well if something does happen I'll take my chances with htc or get a bill from them to fix it. I have seen many cases in where people have sent their device in with am unlocked boot loader and htc seamed the problem a hardware issue and not software. They got the devices fixed for free under warranty. So to me that says that as long as its a defect, and not caused by the software I'm good. No mater most fixes are rarely above $200 and most tend to be in the mid one hundreds from what I've seen.