My wife will be the primary driver, and wants a "tall car" she likes both for different reasons, and was hoping for help

First of all, to the person ranting about buying American, Mercedes own Chrysler, so in a way you are buying American. Secondly, Honda probably manufactures just as many cars in America as the American manufacturers, so you are still supporting American jobs and the American economy with a purchase of a "foreign" car brand. On to the Mercedes vs Honda.
Mercedes review summary "this is the least convincing product to wear the three-pointed Mercedes star that I can recall testing." Source: Sunday Times.

I found a review of the Honda FR-V on the Channel 4 website:(http://www.channel4.com/4car/road-tests/H/honda/fr-v05-/fr-v05-.html), and one in Spanish so I used some Babelfish translation tools: http://tools.search.yahoo.com/language/translation/translatedPage.php?tt=url&urltext=http%3A%2F%2Fwww.km77.com%2Fmarcas%2Fhonda %2Ffrv_05%2F0primera%2Ftexto.asp&lp=es_en

Also the Mercedes review from Channel 4:
http://www.channel4.com/4car/road-tests/M/mercedesbenz/b-class05-/b-class05--costs.html

Looks like the Honda is a better option.
Hope this helps

which ever you can afford

Mercedes don't have that reputation for 100% build quality they used to have. I would ask "what am i getting for the extra money". I think that mercedes are overpriceed for what they are. The japanese manufacturers, expecially Honda, have a fantastic reputation for build quality and excellence. That said the mercedes looks better!
Check out the Which? site (you have to subscibe but you can do for trial period only) as they are a good source of independent reviews.