Only testing, with real sales, will give you this answer. People say one thing, do another.
What you can try to test is information. Testing shows users will go to to a site to buy say, a three megapixel camera, only to realize they don't know what a "megapixel is" or whether that is good or bad.
Then they go off-site to learn. They might return, but probably will not -- they'll buy from an advertiser of an online magazine which reviews scanners.
Honestly, you're asking for false choices with "which of the three" as well. I'd probably start at a site that offers
informative reviews like this one. A site like this supports the entire shopping cycle, which gives it a chance to capture me once I'm there.
From all these sites, I would have to guess your target is the professional scanner buyer or someone who had already done all their homework and had an exact model in mind. There is little facility provided for comparison, or winnowing down your choice.
Most sites aren't shopping sites -- they're buying sites. If the buyer has done all the work, these sites are glad to take their order. If a sales person did this, they'd starve to death. Try a little information, write a little
web copywriting.
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The Catalog of Unfindable Web Widgets ...why can't your
web widgets do this?