I just developed my first roll of neopan 1600, and I've very impressed! That film is beautiful... I exposed it at 1600 and the grain and tones are very nice. I developed in XTOL 1+1 for 7.5 minutes. The only other fast film I've used is delta 3200, which was much grainier and didn't have nearly as nice tones. Whats more is that the delta 3200 negs were very hard to print, whereas these neopan negatives look very printable on grade 2 paper.
Leica M4-p, summicron 50. F2 1/16
Leica M4-p, ultron 28mm. F1.9 1/16
Leica M4-p, summicron 50. F2 1/30