I am using a Fusion Drive on three systems now and I would say that Fusion Drive is definitely worth it - the speed increase over a standard 2.5" 500GB drive in a 2011 MacMini say is fourfold. However there is one issue that you must all realise - and that is, if you order a Fusion Drive with Apple, if you want to set the drives up back to normal use only ie. separate SSD and HD - it WILL NOT WORK (from what I have been told by fellow Mac users here).
This is because the OSX build that comes from a factory-set Fusion Drive Mac is different to one you normally download from the App Store (12C2034 vs 12C60). Not only is the build different, but the speed increase is apparent with this build I believe (400MB/s on official installed system vs 200MB/s on non-factory-set setups).
However what could work is that you order a factory-installed SSD Mac with 10.8.2, and then optionally install a separate HD yourself. THAT would work (to be used as Fusion or separate - I have tested it) - and on a proper 2012 Mac, it still registers decent speeds (over 400MBps under Blackmagic Disk Test).
Fusion is definitely worth it. In any case if you are scared about running it in case of reliability issues - if you backup regularly, you still have Thunderbolt to use when using the new machines in most cases. And recovery is fast with TB. If you use a Seagate GoFlex Thunderbolt Adapter (3.5" version) to backup your Fusion to say a SATAIII 1TB or 2TB standard HD - it can be done in a shorter time than ever before. So you effectively have a very fast and cost-effective system...
This is because the OSX build that comes from a factory-set Fusion Drive Mac is different to one you normally download from the App Store (12C2034 vs 12C60). Not only is the build different, but the speed increase is apparent with this build I believe (400MB/s on official installed system vs 200MB/s on non-factory-set setups).
However what could work is that you order a factory-installed SSD Mac with 10.8.2, and then optionally install a separate HD yourself. THAT would work (to be used as Fusion or separate - I have tested it) - and on a proper 2012 Mac, it still registers decent speeds (over 400MBps under Blackmagic Disk Test).
Fusion is definitely worth it. In any case if you are scared about running it in case of reliability issues - if you backup regularly, you still have Thunderbolt to use when using the new machines in most cases. And recovery is fast with TB. If you use a Seagate GoFlex Thunderbolt Adapter (3.5" version) to backup your Fusion to say a SATAIII 1TB or 2TB standard HD - it can be done in a shorter time than ever before. So you effectively have a very fast and cost-effective system...