Please help! cordless vacuums..what's best?

I kinda have it narrowed down between a Shark or Black and Decker..but idk if the shark 2in 1 is better or the hand held..I mainly need it to pick up after 2 kids, I dont have pets, and I live in a small/med size apt, it needs to work good on carpet and bare floors..i just dont wanna mess with getting the big vacuum out every time theres a little mess. I'm also on a budget of less than $80, please give any info you can even if its another.brand, much appreciated!