We booked an Alaskan cruise and one of the stops was Juneau. My wife and I did an Alaskan cruise in 2015 and we did the same tour. We were with other family and friends and they remembered how much we had talked about our trip that they wanted to experience it for themselves. We weren't sorry.
We were met at our ship and driven to the airport. On the way the driver pointed out the different areas that make up Juneau. When we arrived and checked in we were fitted with boots with spikes for walking around the glacier. They have rain/wind jackets to borrow and I got on just in case I needed it which I really didn't. Since there were 5 in our group, we had the helicopter to ourselves. The helicopters usually seat 6 plus the pilot. The helicopter ride itself was fantastic, it takes about 20 minutes to get to the glacier (we went to the Herbert glacier). Once at the glacier, we walked around and our pilot explained how they are formed and what we were seeing.
Don't forget to bring an empty water bottle or a cup so you can drink some glacier water from one of the many pools or streams that are on the glacier. It's the purist water you'll ever drink!
I would suggest that you book well in advance. It is a tour that you won't soon forget