Car: Jag XF 3.0
Join Date: 10th April 2006
Thanked 2,774 Times in 824 Posts
Have a look on Spritmonitor and you'll see that the average mpg for both cars (assuming 2008) is exactly the same at 46 to 47.
In my experience both are good - but the Audi has a stronger, coarser engine, with a high price and slightly lumpy ride. The Accord is weaker, smoother, lots more kit for the price, better looking and rarer.
The only issues of note with the i-DTEC Accord that I know of are the speakers have a habit of blowing, and the early engine software was a bit poor (speakers are a warranty job and the engine software is done by the dealer in a few minutes).
A friend of mine sampled an Accord when I had one (last year) and immediately sold his Lexus. Saw him the other day and apparently 6 of his work colleagues (all also on company cars) have changed their BMWs and Audis for.... Accords!