As a wireless router it's ok, but I bought it for its ability to share USB drives across a network and I was disappointed: it does not support NTFS only FAT/FAT32 and it's too slow.
I've got two 250GB USB drives – one for music, one for video and I tried them both with the DI-624S. Converting to FAT was a bit of a chore (copy files to another hard drive, reformat drive, copy files back) and FAT can't handle files that are too big so some of my big videos could not be transferred.
I got it all working eventually (the documentation is practically non-existant) but watching a film was very stuttery – it would play for around 10 seconds, stop for 2, play for 10 – very repeatable, very annoying.
So then I tried my music – small files = no stutter? Maybe, but it took that long for it to catalogue all my files that I just gave up. It might be ok with a couple of small USB flash drives but not what I had in mind…