It looks nice.

Maybe it's just the pic, but does the ramp extend all the way to the side of the tank?
You might want to add some texture to the basking area rather than leave it plain plexiglass (siliconing some strips of corkbark on it, for example)---it would help their plastrons dry off better.
Putting something around the back and at least part of the sides (aquarium background, for example) would give them more privacy, and make them more willing to bask.
What's the temp of the water and basking area? What kind of light are you using? A mercury vapor bulb?
How steep is the incline? You might "test" it by holding a pellet in front of them (or individually), slowly moving up the ramp to the basking area and see they/each turtle have/has a hard time getting up it to get to the food (assuming they'll eat from your hand in the first place....).
BTW, what is that turtle on the left in the third pic?
"You become responsible, forever, for what you have tamed." -Antoine de Saint Exupery-