Yes it is normal. Everyone has different tolerances. Some people can take 5 draws and have the energy to do a 30 mile bike ride and some people can take 5 draws and not have the energy to take their socks off. I am jealous of people who are seemingly transported to heaven and back after a few draws. At the end of the day though, those people are the real winners, they do not need much to get stoned and do not need to spend as much money as many other people do.
These carts definitely work for me but i am still thinking about bud on occasion, not because the vape carts are not good enough, but because a good quality bit of bud is simply too good to ignore.
I can never drop everything and concentrate on one method of consumtion, i like to have my finger in a few pies. I know people who smoke hash and will never touch weed, people who smoke weed and will never touch hash, vape and will never touch joints, etc, but i like to do it all. Nothing beats a joint for intensity, but if you want away from tobacco then these vape carts are the next best thing.