Final Fantasy III: iPhone or Nintendo DSi XL?

Last night I completed Final Fantasy II on my iPhone. I’m planning on starting Final Fantasy III this weekend and I have two options, I can play it through on my iPhone or on a Nintendo DSi XL. I’m leaning towards the DSi, but I thought I’d ask if anyone has done both and has any preference. I would probably choose the iPad, but I do not currently have one. After a quick 15 minutes on the DSi I’m leaning towards that direction. The DSi’s two (larger than the iPhone) screens, dedicated D-pad and bumpers are appealing to me after spending 50+ hours playing Final Fantasy I & II on the iPhone. However, the iPhone is with me all the time and I wouldn’t have to lug around an extra hand-held device witht he DSi. So do you have any words of wisdom for me?

~Shooter Out