It depends what you preffer.
Cash games gives you the freedom of play any time and sit out when you want, and tourneys have a more strict game time, specially MTTs, they can take hours to complete, Sit n Go are faster to finish, its like a final table at MTTs, but its not that simple.
IMO Cash games are harder than tourneys, MTTs have a lot of recreational players, and Sit n Go are hard too, more regs, maybe not in micros. So, for me, tourneys are more profitable and maybe easier for a non professional player, but have that strict timeline that sadly doesnt allow me to play them right now (im right now in a hard job that just allows me to be online few hrs per day), and im not playing so much poker, right now i just can play cash games or spin n go, etc.
Another thing to consider is the
bankroll management, in cash games you can start with a 30 buy-ins bankroll, and MTTS have much more variance, so, i recommend to start with at least 100 buy-ins if you want to never break.
There are some other aspects to consider when choice a format, but that are the most important points for me.