I'm a gas range rookie too. I may have been able to learn how to deal with the issues differently, but i chose to get a different range.

I replaced a new Kenmore Elite (a.k.a Fridgidaire) range. Here's my 2 cents.
1. 5 burners on a 30" cooktop is too crowded. If I had a large pot on the center or right-front burner, I couldn't fit another large pot next to it without them touching.
2. Having the 17k BTU burner and 500 BTU lo-simmer in the same burner means you can't do both at the same time. The 12k will boil ok though.
3. The 5k simmer burner is only good at simmering. You won't boil anything quick on it.
4. How low will the 12k, 9.5k and 7.5K burners go? If they don't go down to at least 900 BTU, you have 1 simmer and 1 lo-simmer, but you can't use the lo-simmer if trying to fast boil.
5. Not sure if all their gas burners controls are this way, but when trying to adjust the burner, when going from MED to HI, there is a mark for MED, tick mark 1, tick mark 2, then HI. The flame did not change going from MED to tick mark 1 or down from HI to tick mark 2. The only flame control was between tick mark 1 and tick mark 2. You had to have a steady hand to make fine adjustments. Same way on LOW to MED settings.

We had to constantly move pots around. On the 17k to boil, move it back to the 5k to simmer...

I know I could have used a diffuser on the non-simmer burners, but seemed like a pain to figure out that curve too.

Ended up replacing it with a Wolf which has 3 15k burners that each can lo-simmer at 900 BTU and 9.5k burner that lo-simmer a 325 BTU. No more playing musical pots.

This post was edited by scole250 on Fri, Dec 6, 13 at 11:46

This is kind of late, but I had a couple of things. It would be hard for anyone but you to know what you can or can't live with in a cooktop.

In the price level you're shopping, you will get single ring, sealed gas burners. The sealed vs. open discussions have to do with whether the edge of the cooktop is sealed around the bottom of the burner or the bottom of the burner is open down to a drip tray.

Sealed gas burners have gas ports (little bitty holes) on the outside of the burner head - actually parallel to the cooktop surface. Open gas burners usually have some or all of their gas ports facing upwards towards the pot.

If you haven't lived with gas before, there are a couple of ways in which the "mechanics" of gas burners are different.

You need to fit the pot to the burner size, at least somewhat. Using the frigidaire 17k burner as an example, you can't effectively put a small pot on it. This is because the ring of flame is the burner width plus about 1-1.5 inches. If you place a small pot in the center of the burner, its likely all of the flame will miss the pot. Some times the grate designs forbid having small pots placed anywhere but the center.

There is a little bit more to that concept. The flame will likely touch the pot and spread outwards even further and "climb the side of the pan". The higher the btus of the burner, the bigger the flame will be from each gas port. While flame shooting up the side of the pan can look cool, all of the flame that misses the bottom of the pan is wasted.

Burner designs can be kinda poor in actual use - I think it's from the gas pressure - because the larger the flame from higher btus, the bigger the pan you're going to need to be able to USE those btus. This is because the flame is pushed by the pressure away from the center of the pan and towards the outside.

That is the long way round to saying a little rule of thumb. Unless you regularly use restaurant sized cookware, the bigger the diameter of the burner head, the larger the pot required for the same btus.

To a certain extent, another rule of thumb is when faced with two burners of the same btu rating, choose the smaller diameter one for more flexibility in pan choice. It will put out more btus directly under the pan.

A corollary would be - big burner, big ring of flame, big pan = cold center of pan. You would not see this on an electric cooktop, but you will with gas.

Get around this with heavy bottom cookware or cast iron cookware- but it can be expensive and heavy. Simple stirring works too, Sometimes, an inexpensive, flat piece made out of cast iron is a great thing to have. It can be used to provide the heat transfer - evening out the heat across the entire bottom of a pot sitting on the cast iron.

You can "fix" a poor simmer burner in the same way. Use an inexpensive simmer plate or a plain cast iron single burner griddle or a cast iron pizza pan. They will diffuse the heat from a very small ring of flame and spread it out. If the heat is still too high, use a grate on top to get a little more distance from the burner.

The last thing about buying any cooktop is take some of your important pans to a showroom if you go. If not the actual pan, then some paper tracings. Some cooktops have interesting problems fitting the pans you expect to be able to use together. While you're looking at that, also look at how the pans and the knobs fit together (or not).

Plus some people want a large burner in the back (partly a pan fit issue) and some people want the two larger burners in the front. The cooktops you're looking at show both. I don't have big feelings about the issue, but its best not to be taken by surprise.

You can compare power level between gas and electric burners if you know the wattage of your current burners. A 3500 watt burner is approximately 12k btus. A 4000 KW burner is about a 14k btu burner and a 5000 KW burner is about a 17k burner.
Hth.