The BBC's primetime consumer rights programme, Watchdog, has been featuring BSkyB's digital TV PVR service, Sky+, in recent weeks. According to the presenters they have been inundated with viewer complaints about Sky's service. These seem to focus in general on unreliable set-top boxes (customers often have had several replacement devices), or programmes that have not been successfully recorded.

I have been a Sky+ user since the first weeks of its launch back in 2001. I have seen demonstrations of many other PVR services from around the world over the years, and have personally also tested TiVo's UK version (now withdrawn). In general BSkyB as usual has done an excellent job of hiding complex technology beneath a friendly and intuitive user experience.

But there have always been technical problems with Sky+, and one has to wonder why the BBC is jumping on this particular bandwagon five years down the road. (News Corp and the BBC do seem to enjoy any opportunity to stick the knife in.) The fact that there are nearly 2 million Sky+ subscribers (8% of all UK homes) probably has something to with the "noise" being generated by the average Watchdog viewer.

I had planned to comment on Sky+ a week or so ago, and so it was frustrating but fortuitous to experience another glitch in the system over the holiday period. In fact, the problem appears related to the EPG in general rather than Sky+ in particular, but that wouldn't be apparent at first sight. It relates to Sky's interactive football service, Football First, which presents time-delayed "as live" transmissions of football matches taking place in the previous 24 hours. On 26 December a full round of Premiership games took place and at 9.45pm that night Sky Sports viewers were able to select, as usual, extended highlights of any of the matches. Customer service representatives confirmed to me yesterday that a technical fault meant that viewers were unable to select a match by using the up-down cursor on the EPG menu. If they used this method, the feed would revert to the main broadcast. Selecting the match using number keys on the remote control resolved the problem.

Those of us who had set our PVRs to record a particular game found that, after a few seconds of the expected match (in my case - yes, you guessed it - Spurs-Aston Villa), the video reverted to (of all things ;-)) Man U - Wigan. Not a happy outcome over the festive period...

Sky's answer (after 40 minutes in a phone queue, including a diversion to the wrong department...)? "We can only apologise." Indeed. Boasts that viewers need never miss another programme have understandably become less prominent as BSkyB has grown to realise the true fallibilities of its technology.

There is no question that Sky's hard-drive set-top boxes are not 100% reliable. I don't know of any technology that is. Over the past five years I have regularly seen errors to do with failed recordings, incorrect programme descriptions, failed instant rewind, lost recording capacity, and many others, and have had boxes replaced. It's all part and parcel of the integration of a complex digital media technology with a sophisticated multi-channel broadcast service and most viewers probably accept these glitches as inevitable. Clearly Watchdog's complainants fall into a more exclusive category. In spite of the problems, I can assure each and every one of them that there is no better alternative digital TV PVR platform on the market. More importantly, I think the BBC also knows this, but I suspect we may never hear such an admission.

For BSkyB, Sky+ is an early illustration of the company's growing dependence on the reliability of consumer devices. However much it likes to sell the PVR as a "service" (for which it charges a monthly fee), the reality is that it is a sophisticated software/hardware device that is likely to go wrong. These challenges will only increase as it rolls out HDTV, broadband TV and other advanced services.