Mrs. Grouch and I own a Catrike 559 and a Catrike Trail. Both fold but the trail, which has a 20" rear wheel, folds a bit more compactly.
In my opinion, both trikes are very well designed and are tons of fun to ride. Folding one, once you've gotten the process down, is about a 5 minute job. Both have casters that make it easier to roll them around folded. Weight is around 40 pounds. Even folded, it's still a fairly bulky package. Also, not cheap.
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My greatest fear is all of my kids standing around my coffin and talking about "how sensible" dad was.