Things were simple when I was shooting medium format--I usually shot Delta 400. For rollfilm, I think that when Delta400 was reformulated in 2001, it offered better tonality and only slightly larger grain than Delta 100. I also preferred it to TMX and TMY. Now that I've switched to large format shooting (4x5 and 8x10), I've been trying a number of films because Delta 400 isn't available in sheet film. So far, I've shot a fair amount of Delta 100 and TMX and I prefer the TMX. It seems to edge the Delta 100 in sharpness and tonality. For some reason the Delta seems a little sooty and blocked in the shadows. I'm developing using Pyrocat HD on a continuous roller system. I've been shooting both films rated at EI 64 or EI 80. I'd like to hear some thoughts on how people think these films compare--especially in sheet film, but any observations are welcome. I haven't yet tried the new TMY, but by most accounts--it sounds like a very good film. I'd like to standardize on a single film for most of my black and white shooting and right now I'm leaning toward TMX. But Delta 100 is close and it's less expensive--so it's not out of the running. If the new TMY offers most of the quality of TMX with only a slight increase in grain, it might be worth standardizing on to gain the extra two stops. The qualities I value are fine grain, creamy tonality, and good shadow separation.