Phantom, you stated they're a moderate fairly easy rider. In that regard the stock tensioner will do it's job just fine and control the chain tension.
In saying that, it does have its down fall,... for instance, if you drop down to 5th snap the clutch and punch the throttle, or hard up shifts, it affects the tensioner buy the top slackness of the chain being transferred to the bottom of the chain, inturn the auto tensioner will move up to replace the slackness and can result in a overly tightened chain. The other tensioners mentioned over come this weakness of the auto tensioner.
But if you're a easy rider and not a screaming dancer the stock tensioner will do it's job.
If you have done some heavy acceleration and deceleration riding and your in doubt as you know it's a 5min job to pop the doby cover to check the tension.
I check mine each 500 miles. I learnt the hard way and it cost me a new clutch hub and inner primary case bearing for a overly tightened chain. I haven't done any hard shifting since and the chain is still the same amount of top slack when I checked it last.