I had an apex jr and loved it. It's small but easily upgraded with other modules. I believe someone here is selling one for a great price too. In fact I sold it to him when I upgraded to a full apex
My main use is to prevent the heaters from cooking the tank as they often do. So even though it has no display I can check temps via my computer or S4 phone?
Yep
You just need to have it hooked up to the computer via wireless or wired. then just some set up and you can visit the app. Im not positive if the Jr is compatible with APEX Fusion but if it is then its just that much easier.