This site has the rankings (according to different statistics) of electronic engineering courses. In the end it should come down to where you want to be and where you think you will enjoy yourself. Hope this helps
5. Queens, Belfast
.is cardiff uni is the same as uni of wales?wales,swansea ?wales,bangor?
League tables are all very well but remember they're just a bunch of statistics ... 'there's lies, damn lies and statistics' ... or something like that.
I don't really know much about engineering, but if I was you I would visit all of the universities (if you haven't already) and decide upon where you think you'd be happiest.
I'm completely biased towards Cardiff but I've had the best ever year there and I miss it already even though I've only been home a day.