The B-READY is the US version while the B-DUAL is the UK version and the Strider Plus 4 the AU version. The main difference is centered around the main seat.
Note: There is another Steelcraft Strider Plus 3, which is also essentially the same as the Strider Plus 4 but with 3 wheels instead of 4.
Now, let's go through the differences in detail.
On the B-READY and Strider, the whole seat reclines, which means the seat retains its posture and the hood/canopy will follow suit. On the B-DUAL, the backrest reclines therefore you can achieve a true flat lying position when the calf rest is adjusted accordingly. The hood/canopy on the other hand stays in place. This means the B-DUAL is suitable from infants onwards while the B-READY is suitable when the child is able to sit.
The mechanism to recline both seats are the same, by pulling the lever at the back of the seat.
The second seat is exactly the same for both models.
B-READY and Strider main seat recline
B-DUAL main seat backrest recline
Unlike on the B-DUAL, the harness height for the main seat on the B-READY and Strider can be easily adjusted without the need to re-thread by simply sliding adjuster up and down.
B-READY harness adjust
Foot rest / Calf support
On the B-READY and Strider, it is a foot rest as there is an area that allows the feet to rest on the frame. On the B-DUAL, it is purely a calf support therefore the child's feet will not be able to rest on anything.
The mechanism to adjust them are similar, by pressing both buttons at the side of the seat.
B-READY calf support
B-DUAL calf support
Canopy / Hood
The B-READY comes with a mesh panel window at the back with magnetic flap covers.
The B-DUAL on the other hand comes with a hood that can be expanded by a zipper which will also expose a mesh panel right in the middle
The Strider has both.
B-READY Hood rear mesh panel with magnetic flap cover.
B-DUAL Hood with mesh panel
Strider Hood. A combination of both.
You can refer to the official video and user guides below