The controversy relates particularly to Bell's representation of heaven and hell and who qualifies. In the book, he questions the traditional notion of hell as a place where people will suffer an eternity of punishment for their wrongdoings and suggests that the loving nature of God means everyone will ultimately be forgiven and saved.
"A staggering number of people have been taught that a select few Christians will spend forever in a peaceful, joyous place called heaven, while the rest of humanity spends forever in torment and punishment in hell with no chance for anything better," Bell writes.
"It's been clearly communicated to many that this belief is a central truth of the Christian faith and to reject it is, in essence, to reject Jesus.
"This is misguided and toxic and ultimately subverts the contagious spread of Jesus's message of love, peace, forgiveness, and joy that our world desperately needs to hear."
Some critics have called Bell a "universalist" and a "heretic", and accused him of presenting the world with a "safe" version of the Gospel that overlooks the atoning blood of Christ and judgement.
When it comes to the meaning of the blood, Bell writes: "There's nothing wrong with talking and singing about how the 'Blood will never lose its power' and 'Nothing but the blood will save us'. Those are powerful metaphors. But we don't live any longer in a culture in which people offer animal sacrifices to the gods."
Now Derek Tidball, former Principal of London School of Theology and current Evangelical Alliance Board member, has added his voice to those expressing concern over some of Bell's arguments.
The book is full of "confusing half-truths", Tidball says. What is true is Bell's assertion that the "indestructible love of God is an unfolding, dynamic reality", and he is right to say that all people are "endlessly being invited to trust, accept, believe, embrace and experience it". He is also right, Tidball says, with his contention that eternal life doesn't start "when we die but is about a quality of life lived now".
For Tidball, however, Love Wins "only presents half the truth". While he gives credit to Bell's communication skills and passion for sharing God's love, the theologian also worries that the pastor "ducks some hard issues".
"God's wrath, and his holiness, is touched on only very inadequately and insubstantially," he writes in a review published to the Evangelical Alliance website.
"He says the sacrificial understanding of the cross belongs to a primitive cultural world we no longer inhabit, so he sidesteps a key understanding of the cross.
"He assumes that people will come round to accept God's love in the end, and doesn't see why death is the irreversible cut-off point.
"But why does he think people will 'repent' after death when they haven't done so before?
"He uses some parables that appear to fit his argument but ignores others and uses them all in a somewhat interesting way."
Tidball goes on to challenge Bell's assertion that evangelicals do not engage enough in the world, saying that he ignores the huge and longstanding involvement of evangelicals in helping communities, the poor, and particularly in fields like education, health and homelessness.
Most of all, though, Tidball is irked by Bell's lack of clarity.
"Above all, Love Wins is confusing," he writes. "I can see now why people are asking whether Rob Bell is a universalist (all will be saved in the end) or not, because it's unclear.
"Brilliant communication sometimes gets in the way.
"The book contains volleys of rapid-fire questions but isn't so good at giving answers, at least not clear ones."
He adds: "It's very postmodern, which isn't a bad thing in itself. But its cultural fit does not exempt us from asking how true to the Bible it is."
The Evangelical Alliance's Theological and Public Policy Advisory Commission has discussed the book and shaped its own response in which it recognises that there may be "strong feelings" about Bell's alleged departure from the majority traditional view of heaven and hell.
It called, however, for a debate that is characterised by "respect, humility and grace, particularly where Christians disagree with one another".
In a statement, the EA said: "Love Wins, as its title suggests, is a positive and hopeful book written in Bell's customary winsome style which will strike sympathetic chords with many readers.
"However, it casts doubts on the traditional Christian understanding of hell and the fate of non-Christians.
"Though he does not state dogmatically that all will be saved in the end, Bell appears to adopt a view more akin to 'wider hope' theology which is optimistic that God will ultimately save the vast majority of people, or even, perhaps, all people."
In its 2000 publication, The Nature of Hell, the Evangelical Alliance explicitly rejected universalism and concluded that arguments supporting the concept of restitutionism – the teaching that some or all in hell will ultimately be translated to heaven – were unconvincing.
EA general director Steve Clifford called for a respectful debate on the issues raised by Bell's book.
"Rob Bell is a valued brother in Christ and has felt it important to raise publicly some difficult areas of Christian theology that many people feel uncomfortable with," he said.
"The issues he raises reflect genuine but complex questions that Christian theologians have wrestled with over centuries.
"We hope that Christians who disagree with Rob will nevertheless model how good debate should be conducted."
He continued: "There are deeper and perhaps more crucial questions which should be addressed as to the nature and character of the God that we worship and to his commitment to and care for the earth he created.
"I trust that in this biblical exploration we will discover that both love and justice win."