We went to the Holy Land Experience this past October. We had wanted to visit is several times in the past but felt the same way that you did. This time my dad was with us and as a former preacher it was very important to him to get over there so we made sure that we made the time.
I would suggest it on a short day (ie the first or last day or a day that you need a break.) It had some GREAT shows-the crucifiction of Jesus starts right in the streets and passes through the crowd on the way to Calvary. There is also a petting zoo which is fun for the kids-watch out for the camel, he spits. There is a museum that has ancient scrolls (1st century scroll of Esther is Beautiful!) There is also a replica of an Old Testament tabernacle.
Every Christian or Jewish person would enjoy this park. (Although a Jewish person wouldn't like the Crucifixian play, they could skip that if they wanted to.) It isn't nearly as active as Disney but it is neat to visit so that you can visualize certain parts of your Bible.
One thing that was fun was...about 20 minutes before the Crucifixian show, the Roman centurians came out and stood at attention at the outer parts of the crowd. Although everybody took pictures nobody approached them. I tried to talk my family members into taking a picture with them but everyone was embarrassed. Finally I got exasperated with everybody and said "FINE! I'll take the picture with them." and stomped over and stood between the two nearest us and smiled. Both guys turned inward towards me and gave me a menacing look and growled. I busted up laughing and saud "Hurry up! They are growling at me!" That broke the ice. Everybody realized that they wanted people to approach them and they continued to play with anybody who came to take a picture. It was a fun way to pass the time while we waited for the show to start.
If you've done Disney before and you aren't afraid that you'll miss too much being away, this is an great side trip.