[edit: Ill be updating this post with the reviews posted within. - Simon]
About.com: 4/5 stars
"Oceania is the first Smashing Pumpkins record since [Mellon Collie] to fully stimulate the senses and stir the heart."
AllMusic: 4/5 stars
"These are some of the most memorable and rousing songs Corgan has delivered since 1993's Siamese Dream."
An Focal (author's blog entry): 83/100
"This album is a supreme return to form by Corgan and company."
Antiquiet: 4/5 stars
"Oceania has made it clear that he still possesses the ability to write a Pumpkins’ album, and the new band is more than capable of joining him for the ride."
Artist Direct: 5/5 stars
"God knows how long it's been since any artist built a record that begged to be listened to from beginning to end. [...] Oceania is the year's best rock record and a milestone for the genre."
The Arts Desk: 4/5 stars
The sound has been buffed to an exquisite technical sheen throughout, though the mix of hard rock, prog, psychedelia and electropop will feel familiar to Pumpkins regulars."
AV Club: B
"It may be too late for Corgan to reclaim the alt-rock throne he’s long pretended to have no interest in, but with Oceania he’s finally delivered the Smashing Pumpkins album that everybody wanted the first time he decided to revive the name."
"for the first time in quite a while Billy Corgan and The Smashing Pumpkins sound energised and alive."
Chicago Sun Times: 4/5 stars
"Dedicated fans can feel vindicated. Wayward souls can return to the flock. Doubters can hush up."
Chicago Tribune: 3.5/4 stars
"For once the comparisons to ‘90s Pumpkins don’t ring hollow."
Consequence of Sound: 4/5 stars
"This is the album that needed to surface back in 2007."
Daily Nebraskan: A-
"Once you get used to it, it packs a punch. It’s clear that the band is at the top of its game."
Dance to the Radio: 8.9/10
""Violet Rays" is the song that represents the pinnacle and it is their best song in years"
De Morgan [Translate]: 3 stars
"Corgan's strongest performance in the past decade"
Discubed: 4.5/5 stars
"Oceania is most compelling effort the band has put together since Mellon Collie and the Infinite Sadness"
Gaffa.dk [Translate]: 5/6 stars
"The songwriting is the album through the very top, and it seems as though Corgan has taken back to the creative vein he tapped from back in the 90s."
Gigwise: 4/5 stars
"‘Oceania’ heralds a long overdue return to form and manages to incorporate many of the trademark sounds of the Pumpkins"
Grunge Report: A-
"Overall, this is definitely the best Smashing Pumpkins album since 1998′s Adore."
Las Vegas Weekly: 2.5/5 stars
"It’s mostly unremarkable, with Corgan and his latest bandmates offering little that distinguishes the album from the larger, similarly inconsistent project surrounding it."
London Evening Standard: 4 stars
"Let us welcome the new Barclay James Harvest."
Metro UK: positive
"Oceania is a second coming for the gods of grunge."
New Adventures in Hi-Fi: positive
"[...] his young bandmates seem to have got his creative juices flowing [...]"
NME: 6/10 (print only)
"'Oceania' lands somewhere between those cynical real-world practices and the grand fantasy within Billy's mind."
"The most stirring, progressively interesting Smashing Pumpkins record since the band's controversial reincarnation."
"It’s almost as if the Pumpkins were using this Teargarden set to fully gear up for Oceania, which is the group’s most focused, and solid effort since 2000’s Machina/The Machines of God."
"What you do hear on Oceania is a reawakening of Corgan's ambitions."
"With Oceania, Billy Corgan finally returns his beloved Smashing Pumpkins to the heights of greatness and excess that he walked away from in the year 2000."
PopMatters (take 1): 7/10
"Oceania is [...] proof that integrity and quality of artistic output can overcome any negative impression."
PopMatters (take 2): 4/10
"Billy Corgan can’t ever quite muster up the magic of the Pumpkins’ early years because, to be honest, the songs just aren’t good enough."
RedEye Chicago: 3/4 stars
"Good to hear Corgan recognize a world outside himself, one that will likely be reasonably, pleasantly surprised by what the Pumpkin has sprouted this time."
Rock 'n' Roll to the Rescue: very positive
"Oceania is clearly the best Pumpkins album since Mellon Collie."
Rolling Stone: 3/5 stars
"The at-times-cranky Corgan sounds pretty zonkily content throughout."
Sloucher: 5/5 stars
"I’ve been waiting for this album."
Sputnik Music: 4.5/5 (superb)
"Billy shuts everyone up with The Smashing Pumpkins' latest release."
"I don’t think I’m being hyperbolic when I say that Oceania is Corgan’s best album since Mary Star Of The Sea, and the best Smashing Pumpkins album since … Melon Collie?"
"It is good enough to suggest that Corgan has earned the right to be a cocky asshole once in a while."
"What Oceania is, is the most cohesive sounding album the Pumpkins have released in 17 years."
The Way That He Sings: 8/10
"It’s ok to miss Jimmy Chamberlain but it won’t be because of this album. That’s what a good album does for you – it makes everyone sound better."
Toronto Sun: 4/5 stars
"His best work in years."
Ultimate Guitar: 8.3/10
"Really, when I put my nostalgic emotions behind me, this isn't a bad album and for the current musical environment it is outstanding."
USA Today: 3.5/4 stars
"The current lineup bears no resemblance to the original, save for founder Billy Corgan, the engimatic visionary whose creative engines are roaring with an intensity and creative pluck unmatched since his mid-'90s classics."
Wicked Mike: positive
"There’s no ‘Bullet With a Butterfly’s Wings’ or ‘Landslide’ here (and there are some fillers) but Oceania, as a whole, is fluid like the tides."