It does depend which EU country you were in. The more developed EU countries (Germany, France, Denmark, The Netherlands) all spend substantially more on healthcare per capita (not to mention the private contributions through compulsory insurance).
The countries from the original EU that spend less are places like Spain, Italy, and Portugal. Then the newer EU members - which have different cost structures (i.e. they pay less) and have lower life expectancy (healthcare costs go up exponentially as you age).
When you look at all sorts of quality of care measures, then the NHS tends to be middle of the range. Not the best, but certainly not the worst. Obviously there are some things it does better and some it does worse than other EU systems.
Overall, it seems like the NHS is underfunded, but provides pretty good care when you take that into account, meaning it's a reasonably efficient system.