The main diference between a long versus short wheel base recumbent trike is the long wheel base will stretch your whole body weight across the frame giving you a little softer ride. Long wheelbase recumbents are generally more stable than short wheelbase models, thus easier to learn to ride.
Short wheelbase recumbents have a smaller turning radius and greater maneuverability. They have a more equal weight distribution between the two wheels, making front wheel skids less likely. Shorter overall, they are easier to store and transport by car.
Nowadays most manufacturers also offer a folding option for their trikes as well. So deciding on a long versus short wheel base should be a mater of personal comfort and affordability.
As always, the best way to determine which trike is right for you is to test ride them all. With so many options, fits and features available these days, it is impossible for a “one trike fits all” model. Test riding is crucial. Stop in and ride them all!