Personally, I would prefer to trade micro if we talk about gaining experience for a newbie.
I am not saying that demo accounts are useless. More than that, I think that everyone should start with demo just to learn how to use trading platform. It should be the first step to understand how to open and close the deals, how to use indicators in your trading and add some new lines and so on. Such an activity requires some sort of experiments and freedom, so that a trader wouldn't feel too nerbous and worried of pressing some wrong button to lose everything from his deposit.
However, mastering tradinf platform is only one of the skills that a trader needs to acquire in order to start making profits. A trader should also test trading strategies that he come across on the internet. Surely, the best place where to test them is on demo account. You can see whether this or that strategy actually works and how well it works, and is it worth to use it on real account.
One of the most important thing is psychology which cannot be tested or trained on demo account. A trader needs to bring up his discipline to be strong enough to cope with psychological pressure which appears during trading real money. So, a trader should learn how to be disciplined and emotionally stable on real account, but without putting at stake much money and he can trade microlots.
In addition to that, real account is different from demo account by slippages, spreads and other charges. They affect the overall trading in a very serious way, so a trader should be prepared to include these charges into his planning and trading strategy.