Provia 100 & 400: Color is clean although leans slightly towards blue or green depending upon lighting conditions. Needs to be filtered slightly (81 series), in my opinion, to look really good. I shoot both the 100 & 400 in 120/220 & the 100 in ready loads in 4x5. With this film plus the 81 series you get an almost Kodachrome look.
Ektachrome E200: Longest scale transparency film & easiest to shoot. Color is OK but if you evaluate it carefully you will see a slight magenta bias (especially in the blues) that also kills some of the green color saturation. However, under extreme contrast lighting conditions, this transparency film will render more detail in both shadows and highlights than any transparency film I've shot.
Portra NC: I really like the Portra films. Neutral in color with moderate contrast making them very long scale films. I shoot the 800 speed quite a bit in 35mm, 400 in 120/220 format & ready loads in 4x5.
FP4: I use it for masking transparencies for Ilfochromes & shoot it for some B&W portait work. With Photographer's Formulary MCM 100 developer it gives very rich, smooth tones.
Delta 400: I like the Delta 400 much better than the Kodak T-Max 400 film. The Delta film seems much easier to control contrast through using different developers and changing development times.