The old Puma chipset problems were resolved years ago, and at its best VM is a solid but unexceptional choice for gamers. Your main worries are:
1) Whether you will get connected promptly. Some customers are suffering delays of months, with no accurate information on when they'll be connected.
2) Once connected the big worry is levels of network utilisation. For the vast majority customers this isn't a problem, but if the local network utilisation is high then you will find gaming competitively impossible, and your chances of getting things improved vary between very low and nil.
3) I'd also say that Gig1 appears to have a disproportionate amount of problems compared to other packages. When it works well, it'll be OK for your requirements.
I take it you're aware that even at its best, a cable connection has a higher latency than an Openreach line, and that the analogue technology cable uses is prone to a modest level of jitter? Set up a BQM over at https://www.thinkbroadband.com/broadband/monitoring/quality to see what your current connection is like, then compare it to my own below. You might look at mine and think "wow that's great, sign me up", or from the same data you might thing "wow, that's awful" all depends on your expectations and current service.
