I'm not sure why the other two reviews were so low. It's working fine for me.
The strap is about a yard long. That should be fine for a small tree or fence post. It's standard strap webbing so finding a longer one shouldn't be too difficult if you need it. I'll be using one of the threaded mounts, though.
Yes, it does look like it will be a battery eater. I put in fresh alkaline batteries and it draws down to 80% after only a few pictures, but climbs back to 100 after a short while. It's around 14 degrees F, so that in itself is going to impair the batteries. Of course, how often you take a picture figures in heavily, too. In any case, don't have high expectations for battery life. Consider getting a larger external battery, solar panel, or AC adapter for long-term use.
One con seems to be turning the unit completely off. It's not working like the instructions say it should...the red indicator light keeps blinking every 3 seconds or so. I think the position of the rotary switch is important, but I'll have to experiment.
There's also this big warning that you shouldn't operate the unit without batteries or damage will result. I don't quite get this as it obviously wouldn't run without batteries. Maybe what they're trying to say is not to run it off external power without batteries (I expect the batteries are necessary to retain saved settings).
This device was made in China, so I wonder if the instructions are unclear due to translation issues.
In any case, I'm happy with the build quality, and my initial tests have gone well. I don't expect major issues in the field.