I moved from Sky Fibre to the same package (Openreach 150/30) on Vodafone. No engineer needed as existing fibre. Switch went fine and was actually early - about 18:00 the day before planned date.
There was a noticeable improvement in web page loading. Sky was fine Vodafone but feels a bit snappier. Couldn't say if it down to network or hub etc. Bandwidth test score marginally better.
The new 'Power Hub' is a decent spec.
IPv6 is present with a /56 delegation and works well (same as with Sky).
Decent deal when you take into account a £90 giftcard via MoneySavingExpert. This arrived earlier than expected after about two months.
I have had no need to contact support so far so I can't comment on that.

Update after 2 years and moving on (to toob/CityFibre):
I was generally happy with Vodafone, the only issues were:
No static IPv6 prefix available (even if you have static IPv4)
Both IPv4 and IPv6 change every time the router reconnects
The new addresses assigned could appear to be anywhere in the country so for a while some site's GeoIP was way out (showing nearest store many counties away)
The tobi automated support assistant is next to useless.