Ouch was my thought too - which is why I will be holding off for a while.
I'm glad I held off from buying the Cutwork Kit, which is £199 in UK, as if I understand correctly it seems the cutwork function is included in V5 - though you would still need to buy the cutting needles at £45 a time. I'm told the cutting needles last an awful long time though, especially as you don't use them that much, but again it would depend if you were using them to cut templates or just on fabric.
By holding off on the Cutwork Kit, and just buying the cutting needles when I do get V5, it sort of makes me feel better about spending the £350 since if I had bought the cutwork kit I would be £150 worse off when I do upgrade.
"Life may not be the party we hoped for, but while we're here we should dance". Anon