PEX is a blessing to the do-it-yourselfer. No flux or solder to mess with, no glue, easy to cut . . . wonderful invention.
A word of caution: one of our reporters is doing an investigative piece right now about how PEX can burst without warning, causing major water damage to homes.
I see you have a Rheem water heater - well played! My heater isn't Rheem but my AC/heating is Rheem and it's a great brand, no doubt about it.