Can nobody be bribed anymore ? Just as in every other country with laws against bribes, bribes are still likely to occur. One interesting way for the rich to destroy the democracy is by organizing new voter groups and thus controlling who will be the delegates. The hope however is that in this system this costs the rich more money then it used to do, the people can break away from that easier if they so choose. The wealth is bound to maximums, control over companies and land is distributed also making it harder for the rich to enmass enough wealth to destroy the nation.
Will everyone now work happy ever after under fair conditions ? That depends on quite a few factors. It is for example possible that people out of greed will hire their land out to megalomaniacal operations, and then also buy there, while the laws of company democracy are so thwarted that through social and other pressure inside the company the wealth effectively still centralizes while labor ends up abused. This power can then eat away at social services and fair land distribution as well as corner the market, so that many poor people see no other hope then to seek employ in such companies. You could say that such a nation is destroyed by its own greed; as such it is not even injust that this occurs.
A law is just words on paper, unless there are enough honest people to enforce them, than laws are no more then a sick joke for display in a museum. The same is true for the truth about anything.
This DAVID/9-roads model can be seen as a booster on things like social and economic Justice, peace & fair prosperity; if there is nothing to boost, nothing much will result either. There is even a change that the voter-group system will backfire so that power goes from the top down to the people perhaps more effectively then otherwise causing a more efficient dictatorship. (This backfiring is also described explicitly in the interest of controlling this danger, rather then pretending that it can never occur; see laws about King Rule.) If a people are dumb, greedy, quick to anger, hard necked and impossible to make compromises, this system even if generally followed could be a thin veneer over a disaster of a feudal tyranny that works its way through the set up systems. Once a critical mass of corruption exists in a nation, the system will itself crumble (not being followed) as well.
On the other hand if there is a critical mass of good and honest people, this system could make their work double, triple or who knows how much more effective eventually. Quite a bit is probably going to depend on the power of the word, as good people attempt to show their neighbors and friends the truth about something and attempt to motivate them to do someting positive with their power. The potential of the DAVID/9-roads system is that it might unite more people into one practical program, while affording cooperation with other groups. Another aspect is that it can fairly effectively build itself up from a situation of chaos, and the armed system is such that it reduces the chance of civil war.
Like everything else: it will be what you make it to be. The attempt is to make the most effective Constitutional law, aimed at reducing corruption, crime, war, and economic exploitation of one over the other. However this is a limited goal. Even if it is the perfect system, there is more to society then just its economic and government system ... Although a morality has been suggested here as well, in the end society is what individual people choose to do with their natural freedom.