GUANTANAMO BAY NAVAL BASE, Cuba — The military tribunals held at this isolated U.S. outpost have been lambasted as kangaroo courts, heavily weighted in favor of the prosecution. But most of the convictions so far have led to lighter than expected sentences.

Legal experts note, with some caveats, that all but one of the seven convictions at what are known as military commissions, including a plea bargain finalized Wednesday for a former Maryland man, have resulted in lower sentences than those routinely handed out in U.S. civilian courts for similar offenses.

“The federal courts offer something the military commissions do not: true due process,” said Zachary Katznelson, a lawyer for the American Civil Liberties Union, who was observing the hearing at which Majid Khan, a graduate of a suburban Baltimore high school, pleaded guilty to plotting attacks with al-Qaida.

The majority of the men are being held because they are considered too dangerous to release or because U.S. authorities say they cannot find an acceptable place to transfer them.

About 80 percent of the inmates are held in a communal camp where improved conditions, including access to classes and 24 TV channels, have resulted in fewer assaults on guards and less tension, according to officials who gave reporters a tour of the prison last week.

Officials have said that about 35 prisoners at Guantanamo could eventually be tried in the first U.S. war crimes tribunals since the World War II era. That group includes five men accused of plotting the Sept. 11 attacks who are expected to be arraigned later this year on charges that carry a potential death penalty.

But lower-level figures so far have appeared to fare better. Khan pleaded guilty to charges that included murder, attempted murder and spying for helping al-Qaida plot attacks in the U.S. and delivering money for a deadly hotel bombing in Indonesia. He will receive a sentence that cannot exceed 19 years, if he helps prosecute other prisoners.