I am coming back to the plumbing industry after 15 years in Nuclear Power. There have been a few changes. PEX seems to be the #1 potable water material but I have a few questions before I commit to a specific "brand". Are the "insert" types of fittings compatible? For example, will a "Sharkbite" insert coupling work if crimped with a Nibco ring? If the tubing is the same for all brands under the ASTM standard, should not all the fittings work as well? Are there any known incompatibilities between fitting brands? Are there any known issues between brands of tubing and fittings? Are there issues known about OD fittings (push-on)? Is the tubing OD controlled or ID controlled or both during manufacturing? What is your (everyone's) favorite line of PEX tube and fittings for potable water? Some codes (like Illinois) are rather picky about using insert fittings for potable water. (The assumption is that the reduced ID of the fittings might starve fixture supply.) Does anyone oversize branch supply line sizes to compensate? Also, the resilience of PEX should likely make the use of air chambers and shock arresters no longer necessary, true? Thanks for taking the time to share your recent experiences and knowledge.