I have both a cold-light scanner (Sprintscan 120) and an LED one (LS-8000ED). I would not underestimate the difference between light sources - and I would worry less about a bulb burning out than I would picking the wrong tool for the film I was scanning.
First, I don't know what kind of bulbs were being used in the Minolta scanners, but in my discussions with the people who took over Polaroid's service, I learned that Sprintscan 120 bulb burnouts were very, very rare, despite the heavy use that most examples were being put to (they told me that routine service like cleaning/alignment was pretty much the only thing that they needed to address).
Second, scanners, like digital cameras, can have moiré - or something very analogous to it. You don't recognize it the same way - but you will see it when you scan a relatively grainy 400 film at maximum resolution (like old Tri-X). The accentuated grain becomes part of your data set, it looks excessive compared an optical print, and most algorithms for reducing the size of the file will preserve (if not increase) the grain because it resembles fine detail. I find this highly counterproductive, and it comes out a lot more with the LS-8000ED than with the Sprintscan (assuming you use a glassless carrier with either). The same is true of scratches on the film - which if you are lucky are localized and don't run along the path of film travel.
People will hem and haw about "resolution," but trying to get the last 10% out of a 12,000 x 8,000 scan (or even half that for 6x4.5) is already overkill for any ultimate application (especially since 240dpi is all you need for most digital printers) - and doing so at the expense of the final product can be problematic. I think it's better to do a bicubic sharper reduction from a very slightly less acute file than it is to live with the speckles (or touch out the tiniest dust and scratches).
Third, LED does have the advantage for slide film, since you can crank up the power to see through the dense parts of the transparency. This is where the LS-8000ED shines.
Finally, watch the carrier size. A couple of new 120 scanners have a film opening that might require you to re-cut your film. One of the reasons I still keep the Polaroid is that you can put a strip of 4 6x6 frames into the carrier. You can't scan all of them with Vuescan (you can with Polacolor Insight), but you don't have to hack the strips into smaller pieces. The Nikon only has a 6x20 opening, which means that for things like 6x12 (which already requires stitching), you have to scan single frames.
Dante
I have both the 5000ED and 9000ED and both use an LED. Previously I used Minolta scanners and they were fluorescent.
I would describe the difference as the same seen between diffusion and condenser enlargers.
Personally I prefer LED. They are more stable and longer lived. There are a lot of perfectly good Minolta scanners out there with burned out bulbs that otherwise would still be functional. Really a shame, because those were good scanners.
