Gr8stalin summed it up well for the most part. Rain is an idiot with great DM. Our team unanimously agreed that if he ever stopped being an idiot he'd be incredible. Unfortunately, no matter who told him or what advice was given, he refused to change either his play style or comming practices at all. Billdozer's description was spot on for our entire season, with pretty much zero changes from match 1 to 16.
Rain was also definitely not 'super dedicated to the team' (but maybe he fit in with the memesquad better which drew out the full forces of friendship!!) Its true that all he does with his life is play tf2, but it's not equivalent. Rain was a complete flake. His communication when he missed scrims or matches was 0. His presence during map reviews / demos was 0, what little we did of them. If he said anything other than stale memes or duck noises it was a really fabulous day for rain. The second he learned we didnt want to play another season with him, he removed everyone from his friendslist and -karmad everyone on the team without even bothering to ask why. He's not actually unpleasant to be around, but I wouldn't bother with him for anything serious.