So with Cable Broadband (Virgin Media) and DSL (FTTC) the fibre comes into the local area and terminates and then existing copper/aluminum based network it then used to connect tot hat fibre however they way way that is done between the two different technologies is the crucial point.
Cable Broadband has its Fibre terminated at a nearby 'Node' node then feed an RF signal to a series of distribution cabinets in the local area using amplifiers and coaxial cabling, and from these cabinets the signal is then split up in to varying numbers (32-300+ connections) to feed to properties where it 'can' then be split again to serve multi dwelling units or in shared houses.
I've found some areas in the past where cabinets have been over filled with connections to the point they will not close or stay closed.
Now this is where I tell you hoe Openreach's FTTC connects,
Now while the the fibre only still comes into the the area 'it goes directly' to the cabinet where each properties line connects, (I like to call this a more direct connection) each line to a property consists on a pair of copper cores (or legs) the pair will be then run from the Fibre cabinet, through a combiner (to get telephone signal added into the line) and then continue running through to your property and terminate into a NTE (Master Socket)
The difference too connections,
So differences very, The pro's and con's of speed are that because Virgin Media's network uses high gauge cabling and amplifies the signals that higher bandwidth frequencies and more of them will reach the modem and in return give a lot more bandwidth to play with where as Openreach FTTC uses lower gauge cabling and lower end frequencies and doesn't amplify the signal as it moves through the local network so the distance it has to come from a cabinet to a house impacts how much of the frequency the modem will be able to hear and this determines how much speed it will get.
However because of the 'direct connection' of FTTC the line is less susceptible to issues from neighboring connections and in return provides much more stable and lower latency and more more stable bandwidth, with Cable connections bandwidth that your hub connects to is then shared at a local level as well as at the fibre node,
Latency is often less stable because of 'jitter' caused by other connections and their activities and bandwidth can very up and down depending on the demands in the local area and if demands gets to busy in either downstream or upstream directions the latency will rise substantially and this will cause a lot of issues for most services and the connection.
Currently with everybody working and schooling from home and pretty much living lives on a video call, upstream bandwidth has become more important than ever, this is an area where Virgin's network is struggling a lot due to the limited bandwidth available to share with all those speed hungry users, because when upstream becomes saturated download also suffers as it has to communicated when its downloading and if communications are delayed so is the download, a lot of connections will see packet loss come into play when downloading and uploading on a busy network segment, this will cause applications to struggle with communication too.
Stability is why I recommend Openreach products, even ADSL sometimes, in an idle state n FTTC line will keep a very stable latency (no jitter) and a Virgin connection will show instabilities based on the people in the area around it.
Take my connections below for example, By clicking 'Hub3 BQM and Hub 4 BQM' you will see a lot of blue and green spikes, now these connections are currently idle as nobody has been in or connected in these properties, now look at the 'EE BQM' and see that while it has spikes, these have in fact been caused by heavy usage from myself and a house of 4 all weekend streaming football, downloading and streaming music and YouTube. and from 4am this morning until 10am has been sitting idle.
This line only has access to 65mbps download and 20mbps but yet out performs my 350mb download and 36mb upload 'sold' connection.
I will add some pictures to sow examples from the text above.