I don't know whether overall I think it's a good or bad thing, but I think for Britain it's pointless. The main ideals don't apply to us.
We don't really benefit from the subsidies and the most of the economic benefit comes from the euro, which we don't have. There isn't really much of a threat to the UK from other European countries, and the member states don't agree on many military policies. The open borders policy doesn't really apply either, because we're not a member of Schengen and we aren't physically attached to the continent, so can't drive across borders.
However, I spent the summer in France gaining work experience and was given €1400 to do so. I'll get ERASMUS grants when I'm on my year abroad. Personally, although this suits me very well, I think that's a huge waste of money, considering for the 20 people who went on my French work programme alone (a programme which runs about ten schemes), the EU forked out €24,000. Times that by the number of countries said programme operated in, that's nearly a quarter of a million euros, just for a summer gaining largely useless work experience.
At the risk of sounding like a hypocrite, I don't see much appeal in the EU for the average British citizen, but I'm happy for it to exist when it insists on throwing money at me and will make my life easier when I want to move abroad to work.