Windows Server 2008's installation media allows you to use DISKPART to manipulate NTFS volumes very effectively. (It will manipulate Windows Server 2003-based volumes as well-- both OS's are using the same NTFS version, 5.1.)
I've used the "EXPAND" functionality in DISKPART fairly regularly in previous versions of Windows, but I've had to build Windows PE discs to take advantage of that functionality when resizing boot volumes. Booting the W2K8 installation CD and using DISKPART directly from there is nicer than having to make more WinPE discs.
I haven't used the new SHRINK functionality in the W2K8 DISKPART, but it looks handy.
I don't know if it's strictly "legal" to download the evaluation version and use it for this functionality, but you could definitely do it if you don't have a copy of the W2K8 installation media sitting around.
(I'd trust DISKPART and the canonical Microsoft implementation of NTFS more than I'd trust any other tools. That's no slight on the other tools, but being that NTFS is Microsoft-proprietary, I'd expect their tools to handle their filesystem better than any others.)
Edit: You're also going to get support for Microsoft software RAID volumes by using the Windows Server 2008 setup CD, versus open source tools. (I like the open source tools fine, but the Microsoft solution is compelling to me in this case.)