Does SlapChop work good for chopping up onions?

I have a Cuisinart mini-food processor, available at most department stores for around $40, and it works AWESOME for chopping onions. I have the same problem as you and love this kitchen appliance. I also have the food chopper from Pampered Chef which you can find online if you don't know someone who sells it. I imagine it's similar to the Slap Chop. The Pampered Chef version is great, I really like it but it can't chop a lot at once but for smaller amounts it works really well and it's easy to clean. Some people have an aversion to Pampered Chef for some reason, I cook a lot, have a lot of small appliances and tools and I've always had great luck with Pampered Chef, their products are better than a lot of high-end products I've gotten from Williams-Sonoma and other specialty kitchen stores.