Good Morning Britain launched on Monday, with exclusives from Paul O'Grady and One Direction.
The presenters sat at a glass table, rather than Daybreak's sofa, mirroring the style of US TV's morning shows .
Daily Telegraph writer Michael Hogan gave the show three stars out of five, saying: "BBC Breakfast might just have a viable rival".
"Recent big money BBC-to-ITV defectees, notably Adrian Chiles and Christine Bleakley, have struggled in their new home. On this evidence, Reid should settle in more easily," he added.
Digital Spy's Alex Fletcher called the launch show "quite dizzying" but added "everyone has their best smile on and has done their vocal warm-ups".
The Mirror's live-blogger Rob Leigh said: "They're smiling so much their faces will need planning permission for grinny extensions."
Alongside Reid, who is on a rumoured ??400,000 contract, the presentation team includes former Sky presenters Ben Shephard, Sean Fletcher and Charlotte Hawkins.
Andi Peters was also on the show, presenting a quiz feature called Wheel of Cash on location from Kirkgate Market in Leeds.
The first edition ran fairly smoothly, although there was a slightly sticky moment when the weather presenter referred viewers to the Daybreak website during the 07:45 update.
Good Morning Britain's main exclusive was with Paul O'Grady - giving his first interview since he was in hospital late last year with recurring heart problems.
Digital Spy's Fletcher wrote: "The first 'big guest' on Good Morning Britain is Paul O'Grady talking about his recovery from his latest heart attack. It's not exactly A-list and it's a strange shift from the fast-paced hard news style of the rest of the show. However, Ben and Susanna are more adept at switching between the desk and the sofa than any of the Daybreak hosts ever were."
Yahoo News said the programme had a "shaky start" and listed "teething issues" that included distracting graphics and quick camera cuts.
Reviewer Rachel MacGregor was particularly unimpressed with the opening sequence, noting: "Reid, Shephard, Fletcher and Hawkins each read a news story directly to the camera before the next presenter jumped in with another headline. The frequent handovers meant that we saw little interaction between the hosts to begin with, so any mention of their 'chemistry' seemed very forced."
However, she added, "as time went on the presenters seemed to become more comfortable with each other".
ITV This Morning presenter, Holly Willoughby, was impressed, tweeting: "Good Morning Britain is looking rather lovely... Good morning y'all!"
Regular viewers on Twitter had mixed feelings, with one writing: "#Good Morning Britain looks like loose women crossed with Nintendo Wii's version of Sky Sports News."
But former BBC Three and BBC London television presenter, Matt Cooke tweeted: "Very slick, fresh US look for @GMB - seems to have far fewer ads than usual ITV morning shows. And @andipeters is back too - hurrah!"
Another viewer, Andrew Trythall, tweeted: "#GoodMorningBritain was a great looking show, fast-paced, fresh and engaging. Great directing @errongordon. Well done to the whole team."
And Helena Cauldon also praised the programme on Twitter: "Loved the new-look Good Morning Britain today - great launch."
Kaine Milner wrote: "I'm definitely a fan of this new "#GoodMorningBritain show @GMB, faster paced news, less adverts and just generally better than dreary BBC."
But Patricia O'Neill wasn't impressed, tweeting: "Thought I was watching the wrong channel!! Bring back the sofa with Kate and Aled!!"
And Margaret Oliver tweeted: "@GMB sorry doesn't do it for me.  Bring back Daybreak."
Several commentators likened the look of the new programme to ABC's long-running breakfast show Good Morning America.
"Good Morning Amer... sorry, Britain! Yes, with its four-strong team of presenters - the women clad in primary colours - seated around a big glass desk, and a weather expert who gets to add her two cents to the chat, ITV's new breakfast news show owes a lot to its stateside counterpart," wrote Paul Jones in his Radio Times review.
The Daily Mail, however, was not a fan of the desk, complaining it hid Reid's legs from view.
"Later on the show, however, Susanna moved from behind the desk, giving viewers the chance to catch a glimpse of her enviable pins," it reported.
Good Morning Britain replaces ITV's previous breakfast show, Daybreak, which launched to great fanfare in 2010.
The show, fronted by former One Show hosts Adrian Chiles and Christine Bleakley, saw a temporary boost in viewing figures, but they soon settled back to previous levels and the presenters were sidelined. The show ran through four editors in its brief lifespan.
The name Good Morning Britain was previously used by ITV from 1983 to 1992, and is chiefly associated with Anne Diamond and Nick Owen.
Louise Minchin has been presenting BBC Breakfast alongside Bill Turnbull since Reid left - an announcement about a permanent replacement is expected in the autumn.
Critics and viewers have delivered their verdict on ITV's latest breakfast programme, fronted by Susanna Reid.