Despite critical acclaim, sales of The Big Room were considerably lower than their previous album, Shades of Purple, which Verdens Gang attributed to a lacklustre marketing effort by Atlantic Records.

Citing disappointing sales, Atlantic chose to replace M2M as Jewel's opening act halfway through the tour, after which they returned to Norway and disbanded.

[5] The Big Room took a different musical direction compared to their first album, replacing their bubblegum pop image with a more mature sound.

[2] To promote the album M2M filmed an appearance on the episode "100 Light Years from Home" of the TV show Dawson's Creek in late February 2002.

[10] Verdens Gang attributed the lacklustre promotion of the album to Atlantic's decision to save money following the drop in record sales in the wake of the September 11 attacks.

[14] "100 Light Years from Home" aired on April 17 in the US, and M2M were scheduled to recommence promoting the single and album in the US in May, before moving onto Mexico, Australia and Japan.

[16] In mid July, M2M were removed as the opening act by Atlantic, who cited disappointing sales of The Big Room, which at that time had only sold around 100,000 units in the US.

James Hunter of The Village Voice called the album a "pop masterpiece", praising the singing, songwriting and decision to use live backing instruments.

[5] Chuck Taylor from Billboard said the album featured "a decidedly mature acoustic pop/rock signature, belying the tender age of the act's two singers",[25] and also gave favourable reviews of both the singles "Everything"[31] and "Don't".

Saying the duo deserved an "A for effort", she praised their strong vocals and instruments though labelled some of the lyrics as clichéd teenage melodrama.

[30] The Philippine Star said the album "retain[ed] the same young, sparkling kind of effervescene that made the group such a huge success".

[2] The Massachusetts Daily Collegian gave a favourable review, calling the album "a crystalline example of the heights that teen pop can accomplish".

[29] Karen Tye spoke favourably of the album, saying they had "ditched the cutesy voices and effervescent ditties" and replaced it with acoustic pop and rock which occasionally bordered on country.

Erlewine said they had ditched their sweet and innocent look from Shades of Purple, for "lots of makeup, crimped hair [and] fairly low-cut tops".