I have only the highest things to say about Delta 100 and 400 both.
For several years now, I've used precious little but those two films, but I've tried just about everything...Tmax, Tri-x, all that jazz. Fuji sent me a couple of rolls of their finest, so we'll see...but I'm willing to bet that all around, the Delta will be my huckleberry.
D-100 is a very fine grain film, but extremely flexible. I can push it quite a bit (Ilford only recommends to 200ISO, but I've successfully pushed much higher) and depending on the developers you use, and your techniques, you can pull some grain out of it quite easily.
D-400 is also my sweet huckleberry, because at proper developing times, it has fine grain, and good contrast. For my needs however, it can push very very well, and either create huge grain or surprisingly sharp. I've shot with it at 6400, and gotten some lovely results.
With the proviso: I like grain, I like very very high contrast, and in the last several years, I've only used Ilford developers.
So, if you are commited to other developers, others will ahve to chime in.
There are a lot of good films out there, and sometimes I feel like a putz for only using Delta, but it is so amazingly flexible, it's a joke. For example, I left a bulk roll of 100 and one of 400 in my balcony storage room for 3 years. Cold in the winter, hot hot hot in the summer, and I still get great negatives. I've also abused my negatives by leaving loaded cans in the sun for hours, and I get some very interesting results....the other Ilford films just don't have this kind of latitude for my uses.
