I'd say that as a general rule VM is quite good for gaming. The majority of customers have no problem, get the speeds they expect and (more important than speed for gaming) they get acceptable latency.
A few customers don't get the performance they hope for - either because of the mediocre wifi performance of the cable hubs, or because there are problems on the connection that result in poor latency or erratic performance. And when there are problems, those customers often discover how awful VM's telephone support is. VM's senior management congratulate themselves in every quarterly results announcement about how their customer service is improving, but the reality is that Virgin Media's customer service remains telephone based and is difficult to access, time consuming to engage with, too often offers inaccurate, poor or unhelpful advice, often requires multiple calls about the same problem, and in some cases takes many months to resolve problems. The company's offshore and outsourced support agents are amongst the worst you'll encounter from any company, they won't take ownership of problems, look to transfer any call they can't or don't want to handle, use tactics to close calls that haven't been solved, promise callbacks that never happen, have zero understanding of the technology, and when they don't know an answer, for cultural reasons they are prone to making things up on the spot. Communication between VM and customers is poor and any message from the company should be assumed to be unreliable. There's no proper online account management and little in the way of good quality online support (this forum is the ONLY part of VM's customer interaction that does a decent job, staff are helpful and UK based, but it isn't a real time response service). Everything that VM can outsource on the cheap has been, leading to erratic performance on new installations, hub deliveries, customer contact, even the VM email service is outsourced and cranky with poor reliability.
So basically, when if it works it's great, and that's most of the time and for most customers. Even some support calls are short and successful. On the other hand, getting some things fixed can be a trial of tenacity. As @-tony- says, give it a whirl, but choose wisely in the cooling off period, and also judge the company on all aspects of performance in getting the connection in and working. If there's the slightest doubt in your mind, cancel during the cooling off period.
