I've 2.5 years with Vodafone on a "Pro" 500mb/s Openreach (which is usually more expensive than a CityFibre Vodafone area) fttp connection. Biggest issue I've experienced is there was a phase of being routed through Edinburgh as they were doing network upgrades apparently (I'm in the West Midlands) which lasted around 3 months, though that has now been resolved for the last year or so (i've sub 10ms pings to google/BBC) and no packet loss. Also, within the whole period i've had 90 minutes of downtime (overnight, so the only way I noticed was via logging, which puts me in mind it was exchange works).
Currently back to paying £32 a month after renegotiating in March (as they do the whole % rise every year increase). I use my own router (a homemade Raspberry Pi 5) with no issue and what ChrisD says above is correct make sure they send you the logon details rather than you transcribing, though personally they got mine correct.
For what they charge and for what you get it is a very good service in my experience, but you won't get the same support (but you aren't paying the same price) as other more boutique providers.
Edit - added detail.