I am thinking of starting promoting CB products and wants to know if it gives more income to promote single product to prevent the costumer getting confused among many products or its better to compare many similar products?
The more targeted your landing page is to your offer the better your conversions will be. That last thing you want to do is distract the customer when they get on the landing page. Some niches respond better to different landing pages. If you are going to try a multiple product landing page limit the total products to 2. You want to have your better converting offer as the best product and then have a visibly inferior product there as well.
The best way to answer your question is to build two separate landing pages and do split testing. Since, every niche works different you might end up losing sales if you don't do split testing. I found the individual reviews more effective on the long run for most niches. Getting personal with your readers/customers, reviewing the product from your own point of views and providing credibility is what will skyrocket your conversion rates. Always use unique content on your landing pages/ this is a rule of thumb. Some of your customers might already have read several reviews, and I doubt they enjoy to read the same dupe crap on your landing page too. Al.
If I reasonably can, I'll always promote two products in the niche, because I find, overall, it brings 30 - 35% more sales in total for about 10% more work in total.
Get one product setup and running.. Then try another product in the same niche using a slightly different method and see what results are better. Mix and match to get optimal performance out of just one or both depending on what you think will be best.