Craft 5 was recently released and it looks awesome. I did some testing of it during the beta phase and was impressed with all the new improvements. The entrification of everything and the allowance of matrix in matrix is a game changer.
I will write more about it once I start converting some sites over, but for now I am just prepping them all for this big update. Here is the current list I am following to prep the sites https://craftcms.com/docs/5.x/upgrade.html
Until next time!