I belived both statements are essentially correct. You can adjust density curves for R, G and B channels separately, but not actual exposure. You can't really make precise adjustments. I do fine scanning with FilmGet with minimal adjustments. The key is that I use 48 bit color files, and I make sure all information is preserved-- shadow detail is maintained and highlights are not washed out.

VueScan ( http://www.hamrick.com ) is an excellent inexpensive alternative if you don't like FilmGet. I do my adjustments in Picture Window Pro ( http://www.dl-c.com ), which is superb (the curves controls include histograms) and also inexpensive. So you needn't make a big investment. You need an image editing program anyway. You definitely can't get by with a scanner alone.