It used to be cheaper if you get the collection by buying the Korg microkeys 61, than purchasing the collection itself when it's not on offers. The recent offer is the exception, not sure if it's ended. If it's ended, get the microkeys :) , but only the 61 keys version is packaged with the full collection, I think.
I've collected some hardware synths (D70, Yamaha SY, Alesis QS..) but missed the whole Korg series, so it's good to have it. Just that I've not gone deep into the sound yet, as I seem to use the AAS collection for most of my projects. On a recent project, I was looking for an organ sound in a hurry and remembered there are some in the M1 soundset.. pull it out, but it's not suitable. Ended up choosing one from Dim Pro, DSF libraries.
If you're used to the Korg hardware, I suppose it's immediately more useful.