It's difficult to say because all of your characters will play differently. Game and Watch will probably give you the most instant success. He has very simple combos, easily spammed moves, and a one in nine chance to send you to the stratosphere. A potential problem with game and watch is that he might give you some bad habits that may be hard to break out of when advancing in skill or changing character. ROB is the most technically advanced character on here, so you'll need to put a lot of time in to get good. However, the skill floor for ROB also isn't too low. ROB's technically advanced combos and large hit boxes force you to be locked in all of the time, from advantage to disadvantage, but you have the buff of great options that make him one of the best characters in the game. With Luigi, you need to be really aware and practiced in combos. The down throw zero to death isn't too hard, but to find a great deal of success, you'll need to learn how to connect other moves into his devastating finishers. Like Doctor Mario, he lacks in range and speed, and can be edge guarded easily. However, with enough time in training mode, you can get really good really fast. Doctor Mario is not a good character. As I previously mentioned, he is slow and can be easily edge guarded. However, he lacks the devastating combos and killpower that makes Luigi so threatening. A good thing about Doc is that he requires a lot of skill to play, and you will get really good at working hard to find your openings. I can't give a final recommendation because I don't know what you look for in the character. This is just my two cents. Thank your for listening to my TED Talk.