It is hard to figure out what to make of DroidLaw. Essentially, it is a free legal research and reference tool, but with such a limited capacity for research that I can't imagine any legal professional would be caught dead using it in place of traditional research methods and resources.
The best way to illustrate the problem with DroidLaw is to try a little thought experiment. Imagine that someone has just got into a nasty car collision with someone else and is seeing a personal injury lawyer about a lawsuit. The lawyer gets to work figuring out what he needs to do to get the lawsuit moving by consulting DroidLaw. After the client gets billed some enormous sum for legal research because the lawyer inefficiently spent a lot of time looking up statutes and rules on DroidLaw, a well-written complaint that follows all the rules according to federal court is finally completed and sent to court and to the other party.
A week or so later, the case is dismissed because the lawyer did not file in the right court. For what could be a variety of reasons, the lawyer didn't know that the case should have been filed in state court, not federal court. Had the lawyer used traditional research methods, he would have known better, but the lawyer could not find any information about that on DroidLaw. The client in turn sues the lawyer for malpractice and wins, and a court opinion is written stating that an attorney cannot use a program like DroidLaw to conduct legal research. However, you wouldn't be able to read about that opinion on DroidLaw because it doesn't include a feature to look up court opinions.
These are most of the important issues that prevent DroidLaw from being used as a serious legal research tool: It covers a limited amount of material, the search tools are crude, it is difficult to navigate and read, and it currently has no material available other than certain federal procedural rules (no court opinions, either). It has other problems as well, but I don't want to belabor the point too much. DroidLaw simply is in no way a tool for good legal research.
You can buy add-ons to expand the amount of material on DroidLaw, but even this is pretty limited in scope. Some state law gets added, but so far the only states listed are California, Florida, New York, and Texas. None are comprehensive, and I would recommend against buying any of this material anyway, since most of it can be found on the Internet for free.