personally, I prefer the WLF to the prism, but at the same time, I much prefer medium format SLRs over TLRs. For whatever reason, I find holding a camera in a vertical orientation, like you normally hold a TLR, significantly increases the chance that the image is crooked. For whatever reason more than 50% of the shots on the 30+ rolls I've run through my Yashica are crooked. Come to think of it, it might also be the square format that is harder for me to align. But, in the end, the Yashica sits on the shelf and the ETRSi or GS1 go out with their waist level finders. (I've even gotten moderately adept at framing portrait orientation with a WLF. Its not easy, but I rarely want to shoot portrait. I'm also more successful getting the image straight than I am with my Yashica.)