It depends what you’re looking for in a character. Cloud isn't a difficult character to pick up even if you’ve never played him, or have at least some knowledge of his play style. He isn’t as powerful as he was compared to Smash 4, so many combo starter moves will be slightly difficult to land, like his Nair. Limit Breaker is a move that has to be used in the duration of its 15 seconds or else you’ll lose it, so make the best of it when you obtain it.
Shulk is again a sword character but will take some time to get used to because of his monado arts. Each have their unique advantages and disadvantages that will change your playstyle, but don’t revolve on playing solely with monado arts. You will have to put a heavy emphasis on practicing with vanilla Shulk since his playstyle no longer revolves utilizing monado arts at all times, with his vanilla kit to make use of them with a shorter duration of time. Shulk has decent moves but will be vulnerable due to his long start up time on his aerials.
It honestly just comes down to preference. If you like the generic sword gameplay but with a limit breaker to give you KO potential, then Cloud is for you. If you like a character that can mixup his playstyle with unique traits alongside the playstyle with his sword, then Shulk is for you. Just note that Shulk is a lot more rewarding to play once you get the hang of monado arts.