Ah, I love this question. But then again I love discussing/ranking/rating roller coasters.
I've been lucky enough to ride about 250 different ones around the world. Most are straight ahead "coasters" - a lift, series of hills, etc. Now we have more intricate theming, launches, and even almost true hybrids with the new(ish) Rocky Mountain Coaster company mashing together old woodies with their steel rail I-beam overlays.
Me, I'm partial to classic out-and-back wooden coasters (a la the Phoenix at Knoebels) or even steel coasters that feel like those (such as Magnum at Cedar Point, which is certainly not for everyone). For what its worth, on any given day my "favourite" coaster may change depending on my mood, but in my experience (and many, many others) the single BEST coaster in the world - by some margin - is Steel Vengeance at CP. That is in a category all by itself.
As to the question - I love both EE and Hagrids, and think they are each outstanding types of a different concept. EE is, as mentioned, a traditional steel coaster but with a (very fun) twist. Hagrids is an example of a heavily-themed, story-enhanced ride utilizing cutting-edge technology.
Which succeeds more? To me, it is Hagrids. The rolling stock, smoothness, integration of the visuals, speed and thrills are all top notch. It's probably the best of this type (granted, there are not a ton out there) I've been on. It's also just so much darn fun.
Off topic, as good as they both are, IMHO Velocicoaster tops all. Best coaster ever built in Florida - just a masterpiece of pacing, taking everything Intamin has learned from building other great rides in the past and perfecting it.
Can't wait to get back to try them all again - EE in a couple weeks and Universal at the end of the year.