: What are the advantages or disadvantages of
: getting a watch with a plexiglass crystal?

CONS: Plexi scratches moderately easy, so requires more maintenance to keep it looking great than sapphire does. People who don't know how to polish their own plexi crystals often go around with dull battered ones -- so some people may tell you they are bad simple because they did not know how to have a good experience with them.

PROS: Scratches on plexi are easily buffed out --can be done at home using a product like Polywatch. Replacement sapphire crystals usually run in excess of $200 while plexi ones are often under $75.

Overall given the costs and tradeoffs, I consider both to be fine choices. So I wouldn't let a plexi crystal deter me from buying a watch I was particularly interested in.