You're going to get all sorts of opinions. Here's mine.
I've owned a Gavin for over a year now, many of my dive buddies also have scooters, either Andrew's X-scooter or Rodney's Silent Submersion.
Bottom line is that unless you're diving in a swimming pool or a confined-water area quite similar to a swimming pool, a scooter allows you to get into much more trouble much more quickly than you can get into swimming.
You can get further back into a cave than you can swim out without the scooter.
You can get further back into a wreck than you can feel your way out of after you silt it up. Or simply get further away from your dive boat than you can swim back in the time you have left.
Assuming its working, the scooter will also get you OUT of trouble more quickly than you could without it...currents come to mind.
It's the assumption that its working which is problematic.
If the scooter fails, and they do from time to time, you can be in a world of hurt.
So if you're going to get one, simply realize that your safety may depend on it unless you only use it in extremely benign environments. It isn't simply diving with a motor, theres a bit more to dive planning and communications, etc.
Recommend that you look at any of the three mentioned; Gavin, X, or SS, ...any of them are quality products. All of them, new, will set you back ~$3700 or so to get into one. Contrast that cost with a jetski, a dirtbike, or a snowmobile.
If you're not willing to get into a scooter to that level, I'd advise you to be extremely careful using whatever you DO get. Too deep, it floods. Too long or far, it dies. Its simply too easy to get into situations that you won't be able to get out of, with most of the less expensive products currently on the market.
And welcome to ScubaBoard.
Dive safe,
Doc
