In my opinion (and I rode I305 pre neutering), there are only three things that I like on I305 that I232 doesn't have and those things, to me, are things that almost make them uncomparable.
1. Height - I305 has the height (which i like), but at the same time it doesn't make good use of with the layout.
2. Speed - I love a fast coaster and while I232 is fast, it isn't I305, face (and wheel) melting fast.
3. First Drop - I305 probably has the best first drop of any coaster I've been on. Whether it's because of the angle, length or the speed at which it starts at, I don't know. What I do know is that the first drop was amazeballs.
I said uncomparable earlier because I232 doesn't have these standout characteristics therefore it's like comparing Sea World Orlando's Manta to San Diego's Manta. They both have completely different design aesthetics. To get a better basis for where I232 ranks, I'd look at how it stacked up against the other B&M hyper coasters to get a good ranking (and yes, I know this was for the best of 2010 - just work with me here. Besides, how can you trust a poll that pits World Of Color against Glow In The Park!

That was just painful to watch in the polls, lol).
I ranked I232 "best" not because I'm a fan boy, but because I though it was the better coaster of the two based on my personal criteria. The main factor? Re-ridability. The same thing goes for Thunderhead vs. Voyage. I232 & Thunderhead will always rank higher to me because I can reride them without needing a 30 minute break to get my senses together afterwards.