I believe Deloa's rulers are the same degree of circle on the inside curve and outside curve. I have Ronda Beyer's and I love them.
http://www.quiltersrule.com/Template...as-rulers.html
Her rulers are a different degree circle on the inside and outside so it is like getting two rulers in one. But that said, there are times I wished the degree was the same so I could quilt in all directions more easily. I have all three of the crescent sizes and the medium Double S. (I might have the large as well, I can't remember)
I too have been looking at the quilted pineapple's curved rulers. They look really nice and like Deloa's they are the same degree on inside and outside and she has a special price when you buy the whole set. If I were to invest in more, these would be the ones I get.
http://thequiltedpineapple.bigcartel.com/