Advantages

• Looks and feels like real high quality teak
• No screws - glues down to subsurface
• Forms a water tight seal
• Unique caulking strip eliminates time consuming tasks
• Easy to keep clean, you can even power-wash it
• Wet non-slip qualities are unsurpassed [Tested to ASTM D 4518]
• Stain proof (red wine and fish blood will rinse off)
• Low combustibility - [Flammability testing to AS/NZ 53837]
• UV resistant - [Tested to ASTM G 154-00]
• Low maintenance cost
• Reduced noise (documented at 11 dB) and vibration levels 
• Rain forest friendly
• Lighter weight and faster installation than teak

Trouble with real teak, please also see teak comparison and YouTube

• Color differences
• Leaking plugs and screws
• Leaking caulk lines
• Water damage (often hidden underneath) 
• Bad fittings
• Water stains
• Hard to maintain
• Less availability of quality teak
• Fast grown plantage teak is inferior 
• Heavy
• Hard step noise
• Dropping objects leave dents