I don't have a griddle but the consensus seems to be against a griddle in the 36" size.

Most people do not do a lot of short order cooking but those that do usually buy a dedicated scrapper tool and don't seem to find it difficulty to clean a built-in griddle.

Plus you can put pots and pans on the griddle for dinner.
Most seem to think it is particularly excellent for simmering.

It seems like you may be an exception to the rule and a built-in griddle is right for you.

We don't get a lot of Performer Series reviews, so whatever you decide come back after using the range for a couple of months and post your thoughts.

I'm one of those exceptions... I've had my Bluestar 36" RNB with griddle for about 4 months now, and I love the griddle! I also do a lot of short order type cooking, and use it daily, sometimes several times a day. Once seasoned, you don't really want to "clean" it, just a scrape with a nice wide flat spatula, I find I use my skillets much less often since I got the griddle.

I have a 6-burner 36" Thermador cooktop. I can't tell you haw pleased I am with the Lodge griddle-grill that covers 2 burners. It was only $45 on Amazon. It's a grill on one side (pictured) and a flat griddle on the other side. It is cast iron, one of the best cooking surfaces out there.

We use this everyday. Pancakes, grilled cheese, all kinds of veggies, burgers, chicken, steaks, scallops, eggs...it's very versatile! Talk about grill-marks and the ability to really sear food!

It is a bit smaller than our old teflon-coated electric griddle, but that appliance didn't heat evenly and we seem to have worn out 3 of them in the last 7-8 years.

The Lodge grill sits on the burners most of the time and I still can you the other 4 burners. To clean, I use a metal scrub-brush, gets it spotless. Very easy to keep it non-stick.

That's what I recommend, I love that thing!

I think you can find people on either side of the cleaning preference.
Some other considerations-
The size of the griddle
Add ons like Chef King are 23x14 or Royal aluminum is 23x15
Other add ons and built ins might be smaller, maybe only 11-12 inches wide. Many on this forum have the chef King and love it.

You adjust heat for each half of the griddle separately with an add on

You can choose your cooking surface-
steel or cast iron-machined or textured surface, heavier but holds a lot of heat. Takes longer to heat and slower to respond to changes. Some have observed the heating to be less even but use that characteristic to their advantage.

naked aluminum-lightweight and heats more evenly, responds quicker to changes in heat, takes a little longer to season.

Nonstick aluminum-You have to consider it somewhat disposable.

I looked at the Chef King locally but it was so heavy , but I liked the design. I have used a non stick aluminum griddle that "came with" and I love how even it is and how quickly it heats up. I ordered the Royal aluminum griddle today uncoated, so I will see how it is. I have also used an uncoated smaller vintage griddle but it fits a standard depth range. It seasoned well. Both the Chef King and Royal griddles are 7mm thick.

The main attraction of the built-in griddle is the fact it is very thick (5/8" I think) vs 3/16" for the stove top models, and presumably the burner design covers most of the length for more even heating.

That said, having a griddle break up what would otherwise be a continuous surface is a disadvantage. I like being able to move pans around without lifting them.

I'll go for the Chef King stovetop griddle if I don't get the built in. The built in costs about $700 more than the six burner. As much as I'd love to have one around, I'm starting to lean toward the practicality of just the 6 burner range.

I've heard from a few folks that have them and love them (such as ctycdm above), and read posts where people wish they'd not gotten them.... so hard for me to decide without the chance to try one first in person.

I'm one of the odd ones w/a 36" BS and a BI griddle. I do lot's of breakfast food and use the griddle a lot. I had read a lot of posts sort of 'nay saying' it but since I used to use a stove top all the time it seemed like the right thing to do. I don't miss getting the stove top griddle out that's for sure. Rather than looking at it as wasting space by taking up the spots for 2 more burners I look at it like I have a french plate and 4 burners when not in griddle mode. It works great to keep things warm or simmering if necessary, I've only done that a couple times. You'd be surprised at all the uses a griddle can provide when you look at it as just a big pan.
I clean w/water too, deglaze while hot and wipe down. Once seasoned it's just like any other steel/carbon steel cooking surface, works great. Personally it fits the bill for me and I'd do it again.

I think it's far more flexible to have a removable grill.

Years ago we had a Garland (commerical) range with a griddle. The griddle was so thick it took too long to heat up / cool down. A PITA to clean.

We now have a non-stick griddle that covers the two burners of our Viking range. And it's really easy to clean.

I don't buy into the 'seasoned' aspect. All the seasoning is cooked on grease and food particles.

Well Geoff, sounds like you got it figured out.

I personally won't use non stick cookware but that's just me.

I do 'buy' the seasoned aspect, wasn't a hard sell :)

We all do it different.