If you want to stunt riding then the 24" is better being taller than the 20" cause of the 20" have the tendency of kicking out.
The 20" is mostly for those who want a challenge or want to try something new.
I know this maybe confusing you and i apoligise for that. But i’m trying to help you out as much as i can.
As for the UDC Ultimates. From what i know they come in the 3 sizes as mentioned above. They all have ultra stiff frames so it holds into place.
As for the 3rd question i wouldn’t know sorry but from what my friends tell me. The bedford ones are very durable which must be a good thing.
The 24"s is very good for using around town. Parks etc. plus when you learn 2 ride forward and back. Then you’ll realise, the tricks have only just begun.
Hope i’ve helped you with making a decision even if i have confused you which again i apoligise.
Also i think the 28" is ideal for those who want to learn cause of it’s size. You’ll get some good distance out of it. Then after a while when you’ve mastered the 28". You can move to the 24" then 20"
Good luck, learning to ride it and keep us posted if you need any help
I don’t know either Brendan, but i’m assuming it’s only to show that you have 1. There is no way imaginable of riding it unless you had perfect balance all your life. Having said that. A normal unicycle whether it be trials, muni, or street, BC or Ultimate wheel requires a standard amount of balance.