I'm torn 50/50
I really really wish it wasn't as expensive as it is but there isn't much I can do about that. Having been spoiled by an SSD Air I'm far too used to the speed now.
As a photographer I need to access a large database of large files randomly, which puts Fusion out the window as my style of file access use will rarely, if ever, benefit from the SSD side of Fusion.
Secondly, I won't even begin to know how to open a brand new iMac up and start trying to put an SSD in myself. Not only do I not have the knowledge, but I don't want to have to go and buy tools to do the job either. I just want to open the box, turn it on and have a snappy computer to work on my photos (and the odd bit of video).
If I get the SSD I have to pay £1040 here in the UK for it.
The other option is to get something like this
Lacie external 1TB SSD and the standard Fusion drive.
That's going to cost me £20 more than the Apple SSD (£200 for 1TB Fusion plus £860 for Lacie) but requires I have 'another' hard drive on the desk alongside the current backup one.
Edit: Just spotted that Lacie is £749 from Apple.
This solution also requires me to know for certain (which I do not at this stage) that if I never use more than 128gb on the Fusion, that it will never put anything on the HDD and the HDD will never spin up and potentially slow down anything I may be doing.
Bottom line for me is, given the two options, as crazy as it sounds I'm swaying towards the Apple SSD as even though I'll get slightly less storage for daily use, it means one less hard drive to have on the desktop!