I'm considering upgrading to VDSL with Snap, but I'm worried about a technical issue that occasionally pops up with my ADSL connection and whether this might cause any issues when switching to VSDL.  I'm reluctant to sign up for a 2 year contract if there might be problems.

In a nutshell,  whenever Chorus flicked my account to EUBA it would cause my traffic throughput to plummet every 30 seconds.  I'd get 25 seconds of throughput followed by about 10 seconds of nothing, literally every minute.  Eventually Snap and I figured out the problem and they switched my account back to BUBA and everything was fine.  But every few months Chorus flick my connection to EUBA and I have to call Snap to get them to change to back,  which they're always happy to do.  Snap never really could explain why EUBA causes such a problem, though one guy suggested it could be old firmware at the exchange.

So my question is,  does VDSL use the same technology, or depend on EUBA?  Am I likely to encounter this sort of problem if I switch to VDSL?