I can't tell you how well it works because it's 14 months from order and still counting. But FTTPoD and FTTP are an identical service, so you could as well ask the question of any FTTP user.
Are you able to get detailed line stats from the modem?
There is no "modem" with FTTP(oD): OpenReach supply an Optical Network Termination device (ONT), with a fibre port on one side, and a gigabit ethernet port for you to connect your router to.
As an end-user you can't access the ONT, but there is no "sync speed" to check, because the modulation rate on the fibre is fixed: it's 2.4Gbps down, 1.2Gbps up. As long as you are within optical range it simply works, and if not, it fails.
However, this capacity is shared with other people connected to the same fibre via a passive optical splitter (this is the "P" in "GPON"). Up to 32 services will share the same fibre which goes to the exchange headend - Optical Line Termination, or OLT.
The OLT controls the link and limits the rate of packets sent and received from each ONT, so that the overall throughput you get is what you paid for (e.g. 330/30)
There is a degree of oversubscription, but you'd need 8 users caning the link at a full 330Mbps before they would notice any reduction in throughput. In practice, most lines are idle most of the time. As you rightly observe, contention in the ISP's backhaul network and Internet interconnections is more likely to be an issue.