I really dug Lemons, it felt like the kind of high concept stories that I enjoyed from Red Dwarfs later run.
However, there's a lot to be said for the episodes that mostly take place on the ship and just feature the core cast. These four work really well together, and it's just a joy seeing them do it again after all this time. Am I the only one that found Irene(E) really really hot? I was rooting for Rimmer to hook up with her.