Sorry but what do you mean by "the new QNAP systems that catch up with Synology's performance now"? Are you referring to the TS409Pro or is there a newer model that you are referring to?
I read your latest review in January of the TS409Pro (Read 27MB/s, Write 18MB/S) vs the new review of the DS508 (Read 52.12MB/s, Write 35.04MB/s). There is almost a double of performance here
My main concerns are capacity (5 disk vs 4) and speed. On both counts the DS508 seem to be a better choice than the QNAP. No NFS until September? I can deal with that.....
I'm looking forward to seeing the ReadyNAS Pro too but if they plan to start at $2000 with 500GB drives (which we have to get rid of anyway since we plan to use 1TB or bigger drives), it would be even more expensive than the DS508