I've kept both cars - sold my 2007 Reborn in January this year, but I still have the CL9.
If you're moving from a smaller engine then Reborn is more than good enough and you don't really 'need' the CL9. Here is my comparison based upon experience.
Power: CL9 has way more power, but honestly, in city driving you hardly notice the difference. That's because Reborn is much lighter, hence has equally good initial response.
Grip: CL9 has much more grip, even though Reborn is not bad.
Brakes: Equally good, because CL9 is much heavier.
Comfort: CL9 has a more comfortable ride and seats that are miles and miles more comfortable than Reborn. My CL9's EPS steering feels heavier than my Reborn's HPS steering hence requires more effort at slow speeds. Outside view is much better in the CL9 compared to Reborn. Driving position is equally good in both.
Fuel Economy: Reborn gives around 9-9.5 whereas CL9 gives around 7-7.5 in city with AC.
Parts: In my experience the price of parts and availability, there is not a huge difference.
Features: If you get the fully loaded CL9 it would have way way more features than Reborn. In terms of style, I like CL9 shape much more than Reborn. Interior design of the Reborn is more modern of course.
Resale: Of course it would be much easier to sell the Reborn as compared to CL9.
