I have traveled to Nicaragua twice for pleasure. Have not stayed at any HI property but a Barcelo Resort on the ocean, "Montelimar". If you are traveling for business and need to be in Managua the Barcelo will not do you much good but if looking for an inexpensive all-inclusive then fly down and try the Barcelo property!
As you probably are aware, Nicaragua is the second poorest country in the Western Hemisphere. Take the comments in trip advisor with a grain of salt

. Go and enjoy the country which is a lot less touristy than Costa Rica and mainly an undiscovered jewel for those of us who like a tropical holiday!