Acknowledge Ray's fantastic post above. However I would still feel uneasy about buying a property based on it having VDSL.
In the short-term, VDSL is a viable option as long as Chorus continue to operate and maintain the network up to acceptable standards. Ray has shown this very well.
However as OP is buying a property I would be thinking long-term. I would be thinking about:
1. How long will Chorus maintain the VDSL network up to acceptable standards? 5 years? 10 years?
2. What are my options when the quality of the VDSL degrades and becomes unsuitable? (Chorus has no responsibility to provide you with the best possible service over copper. If your service degrades but is within Chorus' parameters and it costs them more than what its worth to fix it then you may be forced to accept the degraded service.)
3. What are my options when copper is withdrawn altogether? (Not sure how long before this happens in rural areas but certainty something to be mindful of).
4. Are my alternative options (should VDSL be taken out of the equation) suitable? (or in other words, if VDSL is degraded/withdrawn, do I have a reasonable and affordable alternative I can easily switch to?)
I would totes go for VDSL if it was a short-term rental.
For a long-term investment I'd be looking for a property that has either fiber or at least a property with access to a diverse range of options (including WBB, WISPs, a friend up the road with fiber, etc) I can fall back onto.