Since there are many different companies that manufacture electric knife sharpeners, each of them has its own offerings on its products to attract customers. Some advertise how well they work. Others focus more on price. Ideally, you want one that balances these two factors.
Most companies stand behind their product enough to have money-back guarantees if you are not satisfied with their product. Some offer great deals on their guarantees. Others offer some free knives as a bargain when you buy their electric knife sharpener. Different companies have different offers.
Keep in mind that you will have to spend too much money on an electric knife sharpener. You can get some models for as little as $30, but for higher quality, look for around $100. So when you decide to buy, opt for deals on branded models rather than nameless models.
There are many electric knife sharpeners to choose from. Great deals and well-branded sharpeners are well priced but make sure they meet your needs. Most factory brands come with their own warranty on their module or tool when you buy it and this is one great deal, some offer a money-back guarantee as well.
If you try to think, companies who offer a money-back warranty are the companies who have been proven to have good quality on their product or tools, since no company offers that kind of deal when they know their product does not have good quality and material used.