Hi Atrupo,
I've just been going through this - am still going through this - myself. I've just got back into photography after a 30+ year gap. I've yet to develop the first film from my recently-acquired (old) Olympus 35RC, but when I do I'll be scanning the results on my recently-acquired (old) Epson 3170 flatbed.
Meanwhile, I've been scanning a bunch of 40-year old 35mm BW negatives with the 3170. This is my first scanner and the learning curve is, as they, steep. First thing I was disappointed by was the lack of sharpness; just about every shot was soft as s***. Like you, I thought 'must be this cheap old scanner. dammit.' So I fretted and googled, youtubed and fretted...found out about raising or lowering the film holder (35mm in my case) for optimum focus; found out about dpi, screen resolution, tiff versus jpg, emulsion up or down, flattening negatives, the 'unsharp mask filter' (DON'T use it, they all say) etc etc...
After a couple of weeks of mucking about with every variable, I've come to these provisional conclusions:
(In Epson scan - just as good as vuescan for my web-display purposes): The stock negative holder is just fine. Most negatives will curl a little - or a lot - so what you gain in focus by raising/lowering the holder by a mm here you lose there, ie, what's more in focus at the middle may not be at the edges. Personally, I could find no regular, appreciable difference in sharpness in the very narrow range of focus differential that a mm here or there gives you. YMMV. Experiment. Use professional mode all the time. DO use pre-scan sharpening (never more than 'medium' setting, though). Don't bother scanning at anything above 3200. Ony use 3200+ to archive the occasional masterpiece you might one day want to print out poster-size - 2400/1200 or less does just fine for most negs. The one thing I found that does make an appreciable (but still pretty small) difference to sharpness and density is scanning with the dull emulsion side down - contrary to Epson's instructions. Only thing is you must remember to horizontally flip the image in post-process (can't flip pre-scan in Epson unless you preview using 'thumbnail', which I don't - crops the negative). Finally, depending on the individual negative, accept that you will have to sharpen and adjust curves etc - somethimes a lot - in your image editing software.
I know some of that may be heresy, and some of it may be plain wrong. I'm certainly no expert. I'm just reporting the results of my experience so far in the hope that someone will bother to read it and provide, for you and I, the magic formula that'll show us the right way to acceptable scanned negatives on a relatively cheap machine. Meanwhile, what I'm now doing seems finallyto be working, for me.
FWIW, here's a link to what I've been up to:
http://www.flickr.com/photos/105343797@N08/ (pictures from the tinted Fry's Chocolate distressed picture onwards scanned with the 3170 at various dpi resolutions. Pics uploaded before that were scanned by a friend on a V750 at 900dpi.)
Things are, I think, getting better. I no longer regret having bought my old Epson 3170.
