The business on I-offer and eBay is shrinking this year, is it the right time to withdraw from them and go to other platform? and where can we go?
I trust eBay. You can do a lot of business and discover good transactions. I'd say no worries for their services.
bonanzle.co could be an option. Another approach is to go more targeted: Find a marketplace that specializes in the products you're selling. Here's a list of different marketplaces: http://www.sourceguides.com/markets/index.shtml