How to choose a premium dual fuel range (Viking, Wolf, Aga, and the like...) All,

We're considering buying a high quality range.  We have arrested our choice on 36" dual fuel ranges (gas top, electric oven, preferably convection).

Some of those have fairly typical and unique characteristics (e.g., Aga multiple small ovens).  Others are more easily compared (e.g., Viking and Wolf have similar product offerings).

What are the key things to consider before buying a range?  Are there good online resources to understand the quality of those premium brands, especially some frank assessment of Wolf and Viking?  Also interested in personal experiences - customer or repairpeople reviews and assessments.

Many thanks,

JDelage

EDIT:  We eventually got a Wolf set, because I read and heard slightly better things over the Viking, and I couldn't find true comparisons with some of the lesser known premium brands.  Overall, I am happy.  I find that the gas burners don't heat things as hot as an electric top, and ideally I would have liked to have 3 gas burners and one electric element.  We selected to have a grid in the center rather than 6 burners, and it's great but not used very often (but then we wouldn't need 6 burners very often either).  I love to grill veggies on it.

The 36" oven takes a while to heat up. You get used to it, but for the first few weeks, it was obnoxious.  Also some recipes call for changing the temperature of the oven from very high to much lower (e.g., for some roasts), and an oven that size takes a long while to cool off.  The size is convenient to make large batches of cookies, but we haven't needed the width for anything else really.  If I had infinite means or were building a kitchen from scratch, I would get two smaller ovens.
My wife and I are currently doing our kitchen, and have done some shopping specifically in this area. We think we are currently leaning towards a gas cooktop, and then a separate wall oven, for cost and design reasons.

But as we originally planned to do a 36" dual-fuel, and did most of our shopping to date around this, here's a few thoughts/things we learned. Our most important feature was the stove top, so most of these thoughts are about that. We're still not finalized, so I'm also curious what answers others post.


We talked to multiple sales people from multiple local and nationwide stores. There were sales people that told us that Viking &amp; Wolf were comparable. There were sales people that told us that Viking is overrated, not comparable in quality, and even that Viking was the preferred brand. Essentially, we got conflicting reports to where Viking sits. There was no discrepancy however on the quality of Wolf. They all seemed to agree that at that price point Wolf is top (or very near to) in quality, durability and performance.
For the stove top Wolf and a few others have a double stacked burner. This means that you can do a extremely low simmer (melt chocolate on a paper plate), on the same burner you do max it out to stir-fry. There was one brand (dacor I believe) where the smaller burner was hidden behind a cast plate. This seems to me to negate the fast response of a gas stove, but that might be just my perception.
In addition to the double-stacked burners, different brands varied greatly on the versatility of the 5 available burners. 1 15K BTU+ burner, 1 simmer burner, etc... vs. 5 that are generally more versatile. That might not be a problem, you can move pots around as you are cooking, but I'd prefer to minimize the amount of moving I have to do by getting more versatile burners (like the Wolf burners mentioned previously) if I'm at that price point.