I can recommend the Canon 9000f because I can get the most out of it using a different scanning technique. The scanner is cheap, about $150+. Here is my technique. This is the result of months of scanning and experimenting.
You notice I have a 8x10 glass on top of the negatives 6x6. This isn't a normal glass. It is an anti-reflective glass. You can get one from your framing store for under $10. Now, if you try to get the same glass online, it can cost as much as $80. In the picture framing business, the glass is called anti-reflective glass or museum grade glass. I got it for $8. One side has a very fine diffuse surface to prevent newton rings. Newton rings show up when a smooth surface is pressing against another smooth surface like a piece of glass. The ring will show up in the scan. You don't want that. So, you have this glass (the diffused side) laying ontop of the negative, the non-emulsion side. Why would I need this glass? This is the ONLY way to flatten your negatives. Curled negatives would produce blurry scans.
Next, you see that I have a paper mask of the film holder. The mask was a thin cardboard cut out. It is used to tell the Canon software if I am scanning medium format or 35mm negatives. I don't use the Canon software at all but the VueScan software. With the VueScan software, it does not care about what film holder you use. On the right of the photo, you see another thin paper mask. That is to use it for elevating the negatives higher, no more than 1mm, if I am getting newton rings on THE OTHER SIDE (emulsion) of the negatives. The emulsion side, the dull side, is resting completely flat on the scanner bed glass. That glass is not anti-reflective. The only way to prevent newton rings from forming on that side to elevate the negatives a bit higher. With 35mm negatives, I don't need to elevate them because by nature, the 35mm negatives are curling up, away from the scanner glass. When I sandwiched the negatives, it tends to flatten it but without putting a lot of pressure on the emulsion side.
The results? Check my Flickr. I can get pretty sharp scans with my 35mm at 1024 resolution. With my medium format negatives, 6x6, I can get good scans up to 4000 pixels resolution.
Here is another tip if you are using VueScan. Don't do multi scanning. It will cause ghosting effect. It is almost like the scanner is having a hard time scanning the same spot of the negative twice or more.
The deal with the film scanner is that there isn't a mid level scanner. You have the low end ones like the Canon 9000f, epson V500, and V600. The epson v700 (around $600) is considered a low end comparing to the Nikon Coolscan ($2k).
Hope this helps and I know it is too much to digest....