But how democratic is the process really if there's no platform to voice different opinions (not saying that once a decision is reach not everyone should adhere it) and to form an independent opinion? It's agree with us or else.

I can't say I know how many of the Cubans are party members but I guess it's not a majority of the population? And that's what I mean when I say that the political power is aggregated to the party. Even if there was a free debate inside the party they still don't allow competition for the power, just like the income or wealth limitations functioned to keep the proletariat away from power in the early days of democracy.