The advantage is that White-collar fraudsters would not escape justice through failings in the legal system. The judge-only trials would be shorter, more efficient and maybe more effective. The problems of handling complex fraud trials have been highlighted over a number of years e.g. by Lord Justice Auld.
There are other cases that might benefit from being heard without a jury. Trials involving conflicting medical experts, such as the cases involving parents accused of killing their babies, are equally impossible for a jury to assess, and should therefore be handled by judges sitting alone. On the other, the Government has tried twice to remove petty criminal offences such as theft from the scope of jury trial in order to save time and money, but the proposals have been thrown out by Parliament.
Currently there is a split between the judge's role and the jury's. Judges decide on what law is relevant to a case. The jury decides the facts of the case, are they guilty or innocent? The alternative would be to adopt the procedure used in a number of European countries where the judge decides everything facts and law this could be seen as unfair, as a judge is not always representative of society and may be influenced by what he is used to.
There are a couple of significant downsides to jury service. The most obvious is that it is I disruptive to jurors' lives, including having to find cover for both work and home responsibilities. The normal length of service is two weeks but complicated, more important cases can last a lot longer. There used to be a lot of ways that you could avoid serving. This tended to mean that, instead of being tried by a jury chosen from a genuine cross-section of society, criminals were tried by a jury made up of people who weren't working for whatever reason, e.g. students and people with sympathetic and publicly-spirited employers. Certain jobs solicitors were completely exempt from service. The main criticism of juries is that are they able enough to decide whether or not a person was guilty, some cases can be to complex and the jury may not understand what’s going on. On the other hand, I understand where the judge is coming from. Trial by jury is a long-held tradition in the UK, and they shouldn’t lose a tradition. But is society stable enough to decide who’s a criminal and who’s not?
I think that the issue with juries is that they are completely inconsistent, one randomly selected group of 12 voters may be excellent at taking in the information presented, and the next 12 may struggle to understand the complexity of the evidence. However, I do feel that in our society a jury holds a valuable position as it helps to represent the views of many.