Discipline wise they are all similar. They require lots of work and practice, but they're all fun in their own way!
One thing that does make riding easier is good horses. There are plenty riding schools that have horses that you have to kick hard to get them to move, and haul on the reins to stop them (not saying this is right - just often a reality). So try to find somewhere that offers safe horses with refined training so that you can learn the right way to do things without a fight. I ended up buying my horse (after a long break without horses) because I was sick of fighting with riding school horses that required so much work for simple things.
You also want to find an instructor that teaches in a way you'll respond well to, as well as skillfully. There are plenty of great instructors but some are a bit "rough" with lots of demands, others are full of jokes, others call attention to what you are doing wrong... etc. Try to sit in on a lesson to see what it is like. Do the horses look well cared for? Do the riders have to kick and pull to get a response from the horse? Do the saddles fit the horse and rider? \
So many riding schools (including where I learned) are more like mills, teaching basic riding but no skills (pulling to turn, kicking to go etc), then later on you have to relearn everything so make a good decision.