I'm happy I found WGT and hope you'll be successful and around for a long time. I think you have great potential. Here are some of my observations of your current beta, offered up in a constructive spirit and in no particular order:
1. I found the audio level of the music to be much louder than game sounds, so returning to the 'Main Page' from a game made me tear my headphones off and break into an impression of comedian Lewis Black having a tantrum. "Son of a . . ."
2. I think the overall site design is excellent, but adding a friend was not obvious or easy. I searched for the technique and continued to be baffled until I finally noticed the button after almost giving up. The button does not appear immediately. It can take up to a minute before it appears on the members page, inducing another fit of frustration. I don't remember if it is a flash button or not, but maybe it doesn't need to need be, if it is.
3. I found the inconsistent POV relative to the player during the swing to be a little unusual and unnatural. I like the variety of views during ball flight. Very nice.
4. May I suggest that the distance and elevation box and the direction marker (triangle) be separated and not stacked. My intuition wants me to see the exact point where I am aiming and the D&E Box blocks that view. Perhaps it could be offset with a single pixel line joining it to the directional marker?
5. My intuition expects that releasing the left mouse click & hold on the directional marker would remove the grid during putting alignment, as it does when chipping. I'm not convinced that having the flagstick in place while surveying the putt is natural or necessary.
6. I think a linear response on the backswing bar is absolutely essential. I'm not sure it is in all cases. Players like to feel like they are in control of all results, good or bad, and random inconsistencies or the input of some coding-generated inconsistency is frustrating to players. Even the perception that something could be affecting their gameplay is something better left to pinball machines and Las Vegas casinos. A good and consistent physics model will always be a winner.
Good luck. I apologize for anything above that has been said before, or that seems too obvious.