The lower res is right next to the road with a guard rail and low hanging power lines. If you like fishing right next to your vehicle, and don't mind the dust and traffic the lower res is for you.
I personally have only fished the upper res. Its more pleasant to be at and there are plenty of bank fishing spots. Any where there is a pull off there is a path to a bank spot. At the beginning of the upper res. there is a large gravel area people use for a boat launch, also the dam to the right has access through an opening in the fence. You can park and fish here (I have been at this spot when there has been 15 to 20 people fishing). If it is crowded there are plenty other spots up the road.
I can't say there is one better than another, I have my spot
but generally everybody I see are catching.
As for the bite, when its on you can get bit on every cast, no time to set your pole down. Most fish I see are between 8-12" and usually pretty fat. There are some big ones, I have seen them jump and roll but haven't hooked one yet. The biggest I have pulled out would be about 14 1\2" or so. My father-in-law netted a huge 18"er must have been about 4 lbs. All from the bank.
Its a great place to trout fish, it feels like your out in nature, not in Town. For me, front door to fishing spot is about 6 minutes. :dance:
Good luck..
BB