It's difficult for me to say all the differences:
X1:
has the clear/whitish tip
the jump joint uses the same pin/thread as the cue joint
the bumper is black
X2:
has the clear/whitish tip
the jump joint uses a quick release pin/thread at the jump joint
the bumper is white
You have to realize, each cue is a little different. Some X-Breakers are lighter in weight, the tips are shaped differently, the tip/shafts are sized differently, etc.....
Some X-Breaker/Jumper shafts have the leather/phenolic or leather/Xmaterial tips.
I have a black X1, a maple/purple heart X2, and a purple heart X-Jumper with ash shaft (bowling ball material ferrule).
I have a TAP buddy that has 2 X-Breakers, and I have 2 BCA buddies that have X1-XBreakers.
I know another guy that has 3 Xbreakers.
I like my X1 Xbreaker better than my X2. It is lighter, the grip/handle is a smaller diameter, the tip has a dimple in the middle.
It jumps much more effortlessly, and I get wicked spin.
I can shoot jump draw and jump masse shots with my X1, much more easily than my X2.
As far as I know, Richard isn't making anymore cues.....and nobody seems to know what material his clear/whitish tips are composed of.