iPad specific button UX question (rating/feedback interaction system)

Question

TL;DR : how would you design better buttons than my 5 buttons for "I disagree" / Neutral / "I agree" feedback ?

I am doing an iPad application used by participants of an event during a presentation, for example a corporate seminar when CEO ask an audience of 300 managers some questions, to get qualitative audience feedback.

We already made:

• tweet-style Q&A where participants send messages and moderator select best quetsion
• digg-style Q&A where participants send messages, vote up/down quetsions and most popular ones are shown on big screen

Now we want to add a better ranking system that add more info, a 5 level scale

• I disagree
• I disagree somewhat
• Neutral
• I agree somewhat
• I agree

... This way we will be able to determine

• "positive" answers, where most people agree
• "negative" answers where most people disagree
• "controversial" answers, where a certain amount agree and an other amount disagree

this would add more qualitative feedback for presentator, to get instant feedback during presentation, and later when exporting a detailed report.

My problem is how to translate this from a participant's user perspective ? I am not happy with our buttons right now (mockup below)

Knowing that it is not tech-saavy users and we are on a somewhat new device, how would you design this interaction ?

• the star rating system doesnt work as we are on a negative/neutral/positive scale
• having a cursor doesn't work well on iPad

(whole wireframe export is here http://cl.ly/46292f191Z11 )

^{download bmml source – Wireframes created with Balsamiq Mockups}

Answer 1

Graphical representation can work well; it doesn't require reading and has a big clickable area

Answer 2

Ok, so, it seems, you don't really care about neutrality.

Then what about placing the default position to the middle? making it like "hot or cold" or something:

This is based on a potmeter, it could be either dragged or just pointed to the right place.

Maybe this would be over-design, but the key point is that if you don't care about the middle ground, just give that as default, and make people move into the direction which they like.

(Also, since this is a tablet, make it draggable, I guess it'd fit the interface better)

In my country, hot is always at the left hand side when opening a tap, that's why hot is at left, but positive side is usually the right hand side, so it might be need to be turned around.