I guess it really depends on your school, but I know in mine EES is a niche subject, so in terms of internal rankings, it's really easy to get good ranks as everyone treats it as bludge. Even with minimal work, it's not difficult to make it count as part of your 10 units for your ATAR if that's what you're concerned about. Personally, in terms of content, EES has way more interesting topics than Bio but at the same time it has some of the most boring topics if not taught well (e.g. hazards in Year 12). It's also important to note that they both tie in well with other subjects, most notably Agriculture and one another (so EES supports bio really well and vice versa). As someone who took both subjects, I really would suggest it as they support each other so darn well.
If you want to pick subjects that all support one another with these as your focus, there's Ag, Bio, EES and Ancient History (because paleo-related units).
But in terms of them individually, EES has elements of Physics, Chem, Bio, Ancient and Ag, and you'll definitely find yourself using the same skills across those subjects.
Bio ties in well with Chem and Ag, so it's a bit more focused in that sense.
There's also the thing about hard and soft sciences; Bio is definitely a soft science, whilst EES is somewhere inbetween. Whether you prefer one or another is your own thing, but I know some people are really picky about it so...
Regardless, I hope your subject selection goes well for you!