To be a correct rider they are the same. You use your body position/weight to both support and change/ask your horse to perform certain movements.
To just have enough balance/strength to stay on top of one and turn right/left/stop. Then Western is easier there is more saddle to help keep you there. But to be able to RIDE. A western reining horse or a showjumper tackless-thats riding.
Learning should be fun, try to find an instructor who will teach you without "teaching" Try this while mounted turn as hard as you can in the saddle, your horse will turn. So your instructor should be able to help you with circles by doing things like that instead of screaming at you- Thumbs up, heels down,sit up, look up,don't lean,bend your elbows...It IS hard to learn that way.