Most professionals say you should lead out when you hit a flopped set on a rainbow safe board. I agree with this, If you dont get calls, oh well, but if you do get a call or a rasie you are able to easily set it up for a good pay off. The way you should do it is usually bet somewhere between 1/3 to 2/3 pot size bet on the flop representing something like mid pair or even top pair weak kicker. If you get raised by someone with an overpair or a strong top pair you have a few options, you could 3 bet the flop coming over the top if you think youw ill get called and it is a looser more agressive beginner player, if you think they are a tigher player and more conservative you may want to just call the flop reraise and then check raise the turn if at all possible. That is usually my favorite way to play a flopped set to a rainbow board, you will either trap the chips on the turn if they pick up any extra draws on the turn and if not you will get probably end up getting paid the max. I do not like check raising the flop in this situation, it just shows too much strength in your hand and you should utilize that move more often when there are draws on the board. this way it gives you some options if someone calls the check raise and hits the draw ont he board and if not you can push them really hard on the turn to get them off the draw. But if it is a rainbow safe board i would strongly suggest leading out to get max value from the hand, especially if there are a lot of poeple in the hand. If there are fewer people and they play tight i may think of playing it a different way, letting them catch up a little to get max value from your set, but for the most part lead out in a way that doesnt come off too strong or too weak. Good luck.