Thing is, will the player ever know you used behaviors? If you just slap a behavior on something and toss it in your game then yes, they'll probably figure it out and it will seem 'boring and unrpoffesional', especially to other Construct users who know how the behaviors work. The trick is to modify the behaviors with events to the best of your ability, or mess with the settings so you come up with something more unique. The platform behavior, for example, is more of a base for your player or enemy, and not a 'package' so to speak. Once you add skidding, turning, wallkick, double jump, hookshot, and the like..no one will know (or even care) that you used a behavior. The only difference is you didn't spend hours coding ALL of it from scratch.
As far as .97 being 'safe to use'.. I'd say so, with careful planning of course. I wouldn't work on something too ambitious though, save it for C2