Both have their advantages and disadvantages. But I'm curious to know why do you want to switch? What's wrong with 40D? I need to know if the K20D is right for you.
Their is nothing wrong with my 40D i love it and probably won't sell it, because lets say i did and bought the k20d what if i regret it? just thought about maybe switching systems, but i have been using canons for years and i don't think i can;)
Canon 5D II, EF 24-105 f4 L IS, EF 16-35 2.8 L, EF 100 2.8 L IS Macro, EF 70-200 2.8 IS L II, Canon S90, Canon speedLight 580 EX II LowePro Sling Bag 302 AW, Photoshop CS5 Extended, Paint Shop Pro X3.