Long-time fans of Canadian pop duo Tegan and Sara – who are also identical twins – have witnessed a metamorphosis of the sisters / bandmates. What began as a gritty-penny collaboration slowly became a shiny new dime.

Case in point: earlier albums released in the early-to-mid 2000s like "This Business Of Art" and "So Jealous" featured a scrappier, punkier sound. By 2007, with the release of "The Con," fans started to detect a more polished sound that continued to evolve with "Get Along" in 2011 and "Heartthtrob" in 2013.

Not that there’s anything wrong with that.

The epitome of the transition from punk pop to straight-up pop came with the theme from "The Lego Movie" and the song "Everything Is Awesome" which they collaborated on with the American comedy musical group "The Lonely Island." 

Fans accustomed to more intense lyrics from songs past, like "Maybe I would have been something you'd be good at" and "I just want back in your head," might pine for more than the simpler words.

But "The Lego Movie" and Tegan and Sara Quin have more than a theme song in common. Both remind us that contributing to mainstream culture doesn’t always mean sacrificing artistic expression or not challenging the status quo.

This was apparent tonight when the sister musicians – who were both clad in black outfits and a similar short-cut hairstyle – brought their "Let’s Make Things Physical" tour to the Big Gig for a 10 p.m. show on the Briggs & Stratton Big Backyard stage.

In short, although less edgy, Tegan and Sara are still sharp. Less moody, snarky and indie than past shows – and way more perkier – but not fake. They definitely have a genuineness that continues to shine.

The majority of tonight's set list was drawn from the most recent release, "Heartthrob," including the opener "Goodbye," along with "I Couldn’t Be Your Friend," "I’m Not Your Hero," "I’m All Messed Up," "How Come You Don’t Want Me," "Drove Me Wild," "I Was A Fool," "How Come You Don’t Want Me" and the closing tune (before the encore) "Closer."

A few cuts came from the 2009 release "Sainthood," including "Sentimental Tune," "Shock To Your System" and "Alligator Tears."

They did offer a few old school favorites, including the moodier "Dark Come Soon" (for an encore) as well as "I Just Want Back In Your Head," "The Con," "Walking With A Ghost," "Livingroom," "I Know I Know I Know" and "Monday, Monday, Monday" which Tegan introduced as a "12-year old song" that was so old it was a "senior citizen song."

Fans of the sisters Quin know that they have a solid working relationship but keep their distance in their private lives. The banter between the two has always offered an endearing tension onstage which was evident tonight as well when Sara told Tegan to stand under the American flag next to the stage and sing the national anthem as a punishment for messing up on "Monday, Monday, Monday."

Oddly, they never introduced the band  – which consisted of four male musicians. Regardless, Tegan and Sara were really upbeat. They commented briefly but energetically about the delicious smells of the festival and how happy they were to be in Milwaukee despite a 3:30 a.m. trip to the airport.

At one point, Tegan said they had two songs left and planned to "rock the f-ck out of this place" which was reminiscent of the punkier band past. But despite the change in tone and more-techno-focus, the sisters continue to deliver a high-energy show and were clearly enjoying themselves on stage.

On a side note, I would have liked to have seen Milwaukee’s Vic & Gab play an earlier slot on the same stage – instead they played a 6:45 show at the U.S. Cellular Connection Stage – mostly because they have a similar thing going on. (They are quite possibly "Milwaukee’s Tegan and Sara.")

But I’m not complaining. It was a beautiful, warm night at the Big Gig – it was well attended but not overcrowded – and, in a world filled with sadness and suffering, everything really was awesome.