There's been a couple of conversations online elsewhere about the Gopro 3+ having a different lens that favors focus on objects closer than 3ft. The wide shots have been reported as softer. However I haven;t seen first hand whether this is the case or not. I have both cameras and will do a back to back in same conditions to test.
One thing I do know is the 3+ has much better battery life and also the wifi has better range.
I attach my remote on to the bar with zip ties. I have the velcro strap for it but I worry it will come off in a wipeout.
I'll be on the water again in a week so will post the comparison shots.