Depends on the experience. Worth is individual. I have no issues with a great experience even if it is shorter than average.
Not to mention I will probably play through the game a few times if I enjoy it before shelfing it. Plus I tend to take longer during my playthroughs than most people. I stop and look around, take in the scenery so to speak quite a bit.
So a "10 hour" game to most would probably be 15 to 20 for me first run and I would squeeze a few more play throughs out of it resulting in probably around 35 to 40 hours total.
PSN ID: sled_dogs76 60" Pioneer Kuro Elite PRO151FD, Yamaha RX-V3900 A/V Receiver, Oppo DV983-H player. Coming soon: 2 Seaton Submersives from Mark Seaton