Hi,
Right now I'm on S5 LTE. Is it worth upgrading to S7 LTE? I'm still in two minds about doing that.
That's entirely your decision to make. Worth is relative. For some folks it'd be worth it, for others it wouldn't.
Look at the feature differences and their impact to your usage, look at the cost of doing the upgrade relative to your standard of living. Would the real world benefits to you be be worth the money spent?
Generally speaking being undecided likely means you've not yet identified any clear reason to upgrade.