Nikky, Welcome to TFP!
Both the core and the edge are "easier" to install. The core seems to have the most issues, the edge fewer and the least with the RJ series.
The Core only has four power settings, 25%, 50%, 75%, and 100%, so you are going to have to adjust both run time and power level to dial it in. That would be a deal breaker for me. The RJ has 5% output increments, so less fiddling.
If you are going to maintain your pool, you need a proper test kit. Link-->
Test Kits Compared
If you are going salt, you need to get the SALT version of the TF100 and TFPro. If you get the Taylor K-2006C, you will need the K-1766 Salt test in addition.
You test your salt BEFORE you add salt, because all forms of chlorination add salt to your pool. You might be surprised at the existing salt level.
Then you can use Pool Math to calculate how much to add based on your current salt level and the salt level required by the SWG. Link-->
PoolMath
Hope that helps!