I own a 2001 MDX (yes its almost 11 yrs old w/218K miles) and now since my children are grown and gone are strongly considering the smaller 2013 RDX. You have one child and perhaps two in the next few years. Go for the MDX (Its not that much more $). You will use the extra space especially once your kids start having their friends join you. You wont regret buying the larger car, but you might regret buying the smaller RDX. And I just love the MDX when the 5 of us go to the beach. Cant beat it for size, comfort versatility. IMO Also, it seems our local dealers are trying to "get ride" of the 2012 MDX, and are willing to come down on the msrp. The RDX is a hot seller and you wont get much of a price break. I know -- I'm try to work a deal now. Buy a slightly used MDX and save even more. Get the extended warranty as well if you plan on keeping it a while (over 100K miles).

Regarding the regular gas usage in the RDX: I brought up the info on the web site w/the sales rep as well. The MDX says dont use the lower octane it will damage your engine (my paraphrase) but on the RDX you can use lower octane but you might also experience less MPG. They're different engines. My sales rep talked w/the factory and he was told you can use regular gas but watch your MPG. For what that is worth.

 

Moved thread to the new 2nd gen RDX forum.