Agreed - VTL is not a big deal
7 years ago VTL was a big deal because you wanted a Virtual Tape Library to 'pretend' to be a real one. You got performance improvements, replication, etc, and most importantly easy integration because this disk thingy looked & smelt like a tape library. Heck, it even came with tape library personalities. Fast forward 7 years and all the decent backup products support IP or FC attached disk pools. Thus, you don't need all that tape library emulation and even if you DO want a real tape (long term archive, etc) you can easily duplicate from your disk pool to tape. So, NTAP has a pretty good de-duper on it's IP storage and thus you could argue that neither it (nor anyone else) really needs VTL.
Now, the problem I see is that NTAP has a post process engine in its primary filesystem and DataDomain has real time in its secondary filesystem. RT is a much easier sell these days, now that performance is good. But Sun's expected release of RT de-dupe in AmberRoad is a big deal to DataDomain and NTAP: it'll be the first RT de-dupe in a primary filesystem. Lets see how they respond to that.
The de-dupe market is certainly hotting up, but forget the VTL end of it. It's the fag end.