Have been using folders for the 45+ years that we've been out cruising. I still have our original stainless steel 16" Dahons in the barn. The small folders are not ideal when biking long distances, so when we were sailing on our Island Packet 31, I bought a couple of cheap 24" bikes. Pull front wheels off and stored them in the 31s large cockpit locker. After getting tired of breaking down the bikes, went with all aluminum frame 26" folding Dahon Matrix. Great bikes and we still use them biking from home. When we moved to the Nordic Tug 10 years ago, could not easily get the Matrix bikes into the engine compartment, so I purchased a couple of 20" Dahon Mariners. Unlike the Matrix, the Mariner has a lot of "rustable" components, and frequent doses of WD40 are required.
Since we hang on a mooring and anchor out most of the time, getting bikes to shore is a hassle. Our bike riding on the boat has declined a bit (we're in our 70's). I usually leave the bikes on shore at our home boat yard, use them around the boat yard, and only take them on board when I know we will be going somewhere where we will take the bikes off for several days (Block Island, MV, Shelter Island, etc). Plus, in our old age, we've discovered shuttle buses (Duh). If you cruise the North and South Forks of Long Island, there are shuttle buses running from Orient Point, through Greenport, Riverhead, the "Hamptons", right out to Montauk (75 cents Senior rates!). And walking is still an option. Anchored out in either Montauk's South Lake or Block Island's Great Salt Pond, the wife would rather walk into town. We confine our bike riding to touring long distances at selective cruising spots.
Bottom line, bikes on board are a definite PLUS. As far as brands, we have 6 folding Dahons, the oldest pair are the stainless Dahons that are over 30 years old. and still useable. Prices today are pretty outrageous for quality folders. Our Dahon Matrix cost $500 each over 15 years ago, today $700. The Dahon Mariner is a $600 bike. Some people simply purchase a couple of cheapy Walmart 26" bikes, treating them as throw-aways. Break-em down by pulling off front wheel (quick release front wheels are best), and throw them away after a couple of years when they rust out.