As a consultant I feel that others want me to say Scentsy is the best but I think we all have our own opinions. I personally haven't tried the Walmart brand but I have had customers switch from the Walmart brand to Scentsy. Everyone is different and likes different things. Maybe you should try both out and choose for yourself :)
Yes, the Scentsy scents last longer then the ones from Walmart. Also if you spill the scented wax it will come out fairly easily. The Better Homes and Garden brand will ruin your carpet or whatever fabric you spill it on .