Generally you'll find people don't much like island or peninsula cooktop solutions here--harder and more expensive to vent, and potentially more hazardous (depends on size of island). So make sure you've resolved those issues. That said, our range is on the peninsula with built in downdraft and while the venting is not ideal, it's OK for what we do with it. Here in California, we grill most of the things that would make a lot of mess and smoke.
I do like having nothing at all above my head when cooking--I used to occasionally hit my head on the corner of the fan at our old place

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Perhaps you should post a plan?