This question gets asked and answered a lot around here - you might want to look at some of the previous threads, using the 'search' tool.
However, not to belittle your question, it's a good one. Although we all have differing opinions on scanners here, I think we can all agree on a couple of axioms:
1) You get more if you pay more.
2) You can get a lot for a little if you shop carefully and consider your needs.
If you need to scan MF as well as 35mm, then you either have to go the expensive route with a dedicated MF scanner (Nikon or Konica Minolta are all that are left here, I think); the ultra-expensive drum scanner route (commercial stuff), or a flat-bed scanner with neg-scanning capabilities (Epson, Canon, HP and others all offer models that do this).
I have an older Epson PHOTO Perfection 2400 with an optional transparency adapter (6x9 and 4x5) that I use for MF and LF negs. Works a treat, I'm very happy with it. There are much better ones out there now, and they don't cost the world.
For 35mm, you can go with Nikon, Konica-Minolta and a few others and get a dedicated film scanner. For the most part, I think we tend to agree that Nikon and KM are the ones to beat - the others are much cheaper, but tend to be not as nice (no offense intended). You can spend a little for something like the KM Scan Dual IV (which I have) or go up a bit for the Nikon CoolScans. Again, you tend to get what you pay for - spend more, get more.
I'd stay away from some of the lower-end brands like Pacific Digital, but otherwise, it is kind of hard to go too far wrong - just consider your budget and what level of output you'd like to achieve.
Best Regards,
Bill Mattocks
PS - As to 'level of improvement' that you should get - I don't know the model you mentioned, so I don't know how it's output looks. I do know that my KM Scan Dual IV gives me TIF files that can be of much higher quality than my new digital SLR camera at 6.1 megapixel (of course, this also depends on my skills, my lens, and my ability to clean up dust and scratches in the negs, etc). I could blow up my best digital SLR photos to maybe 11x14. I feel confident that I could go poster-sized with my very best 35mm slides scanned at 3200 dpi. That tell you anything?