If it puts on weight at the beginning it really means you probably need it. Weight isn't bad when it's muscle. Jump on the body fat scanner and track BF instead of weight.
Easiest way to stop the water retention is to increase water intake and hit the sauna.
There's really nothing outside of working out and and eating well that has the ROI of creatine. I've seen some estimates of 2-5% increase in gains and capacity. After the honeymoon phase, that's huge.
I started taking it around this time last year. First 3 weeks I didn't notice anything and then boom. My lifts skyrocketed. It was unreal (you can probably find my posts). All my lifts jumped probably 10 to 15%, when they haven't really moved in years. I loved what it was doing. I was singing it's praises to everyone in my life that didn't care to hear me talk about it lol.
But then had to stop lifting for a few months because of a sick parent.. and what I found was that I kind of just shifted over to being a beef cake (I was also stress eating and drinking, so it wasn't just the Creatine)... but I've hit some good progress getting back to the gym consistently. If I can keep this going I might jump back on.