Pros: Cannot think of 1. Don't waste money.
Cons: No Support, No Logs, Nothing really works beyond the basic file sharing.
The bottom line: Lack of necessary features and no technical support. Not worth it.
I've bought the Promise NS4300N from Frys Electronics in Mountain View,CA as I'm interested in getting a All in 1 box that simply works.

After comparing specs from various boxes, the Promise NS4300N seems to meet most of my needs.

1. SMB and NFS - Well, I have not test the NFS yet but the SMB is broken. Speedwise, it's reasonable but if I copy files or directory into NS4300N using XP, I need to refresh the screen before I can see the files. Which don't happen if I copy the files into a Window Server.
2. DLNA plain and simple - just doesn't work. I sent 1 emails and try getting support 2 times through the eSupport but no response. I don't think Promise is too interested in supporting this product.
3. Lack of features :
Defragmentation - No Tools for defragmentation.
Logs - No ways of controlling events logs , e.g , who access the files, ftp,etc. Cannot control level of logs.Logs are too simple. Insufficient even for a SOHO , much less a small office.
Downgrade - Cannot downgrade to the previous firmware after upgrading.
At USD400/= without any HD, it would probably easier for me to build a high end PC using FreeNAS and a decent SATA RAID card and still get change back. At that price, I would expect to at the very minimum get some email response back to the technical problems.
Normally if a company doesn't response to supports emails, there could only be a few reasons, one of which is that they knew there is a problem but they have no solution and are just dragging their feet.