There's a jarring difference between this Shake Shack and the Burger King next door

Shake Shack, the world's hottest better burger chain, went public on Friday amid a rapid global expansion.

Burger King is part of the old guard, one of the uninspiring fast food behemoths that is at risk of being disrupted.

For a direct comparison, we went to downtown Brooklyn, where the two share a small triangular building across from the Kings County Supreme Court. I saw the stark differences for myself on the day of the IPO - and yes, the prices at these two restaurants are comparable.

The differences are striking. The Shake Shack's storefront is modern, clean, and inviting.

The Burger King is a bit dirtier, with many of the windows covered with signs and a shabby flag flying above.

I visited the area at lunch time on a Friday and both restaurants were busy with customers. Inside the well-lit Shake Shack, I found the short and orderly line, cordoned off with retractable dividers. It took me only 4 minutes and 40 seconds to get to the front and place my order.

Inside the Burger King, there were an equal amount of people, but they were lined up in confusing and messy queue. Waiting to order here took much longer than Shake Shack: I waited for more than 11 minutes.

The kitchen in Shake Shack looked clean, shiny, and new.

The Burger King kitchen didn't look quite as clean or shiny, but it looked like your average fast food chain restaurant. After ordering, I waited for my food at Burger King for four minutes and 32 seconds.

Conversely, at Shake Shack, even though I was given this fancy buzzer wand, I still had to wait, along with a crowd of other hungry customers, for more than 8 minutes for my Shack Burger and fries. This was one of the only positives in the BK column.

Once I did get my food at Shake Shack, though, the condiment stand was fully stocked with anything I'd need.

Burger King? Not so much.

I sat down in Shake Shack to eat my delicious-smelling food. The seating areas were light-filled and looked clean and minimal, with wood accents, lots of windows, exposed brick, and interesting art.

Burger had two floors to Shake Shack's one. I sat on the lower level, which featured darkly painted walls, somewhat outdated light fixtures, tiled floors, and standard fast food booths and swivel chairs.

Let's talk about what really matters: the burgers. I ordered a Whopper and a small order of french fries at BK. The burger, while a bit sloppy and flat looking, tasted like the Burger King burger I was used to. The patty was a thin, uniform shape and had clearly been previously frozen. It had that signature "flame-broiled" taste but sort of lacked flavor otherwise. The cheese wasn't very melted and tasted a bit of plastic. The bun was starchy but I do love those sesame seeds. It certainly was amazing, but fast food is like sex: even when its bad, it's still pretty good.

As a side note, my favorite part of Burger King used to be the extra crunchy fries. Seems like they've done away with that, in favor of these thicker cut steak fries. That was a bummer.

At Shake Shack, I ordered a Shake Burger and fries, the rough equivalent to Burger Kings' Whopper. The extra wait proved worth it, as my burger looked delicious. The bun was fuller and the patty had signs of freshness.It had clearly been cooked on a stove top, and the cheese was fully melted. Even the presentation was nicer, with a metal tray and wax paper.

The fries, however, left a little to be desired. They had a frozen potato taste to them that turned me off. I didn't eat many of them.

Shake Shack had other things to offer that Burger King couldn't, like alcohol for sale...

...and daily specials, sourced from local vendors.

They even had a display describing the origins of all their ingredients, like the bacon for their bacon burgers,. The food was purported to be all-natural and sustainably grown. Also, you can buy t-shirts.

Burger King didn't have anything like that.

And, in case you think I forgot, I checked out one of the most important parts of any restaurant: the bathroom. Burger King's was a multiple-person bathroom which didn't look like it had been cleaned in a while.

Shake Shack's bathroom was a single-person room which was both larger and cleaner than Burger King's.

If you've read this far, it's clear that I had the better experience at Shake Shack. I know what you're thinking: you get what you pay for, right? The Shake Shack experience is nicer because they charge more for their products.

Here's the thing, though. They don't charge THAT much more.

At Burger King, I paid about $7.50.

At Shake Shack, I paid about $8.20.

Now, I know for some people, that extra 70 cents can mean a lot. But for most, it's a small price to pay for a better meal.

And, additionally, the Shake Shack meal was slightly healthier, with 960 calories to Burger King's 990.

So, unless burger significantly steps up their meal quality, or significantly lowers their prices, you'll be seeing me at Shake Shack every time.