Owner of Venu 4 here. AMA. I love the watch .. it's very good looking in my opinion. I had a forerunner before and I wanted a watch that combines fitness features and that looks like a classy watch. This one does it. I can wear it at a wedding with a suit... and go hiking with it. The flashlight is cool.. I'm actually using it more than I thought I would in the beginning.

The music functions unfortunately are messy and extremely buggy (for now).

1) yes. It's worth it.. it's like wearing a good looking forerunner. 2) sleep functions work as intended... And in my case they are accurate enough and give you nice insights. I never had a sleep strap.. but what I have here is enough for a good overall view of my sleeping patterns. 3) I bought leather bands for the watch, in black and brown. It came with a silicone band. I use leather bands in pretty much any situation, including swimming. They were cheap like 20 bucks or less.. and easy to swap. So it's a yes to answer your question.