Spin Master's BB-8 feels authentic. It's the same size and shape as the cinematic model, though with plastic construction in lieu of metal. That makes it light enough to bring to birthday parties, bat mitzvahs or your nearest Star Wars convention. Using the included remote, you can have it glide smoothly around the floor, with the head maintaining its perch on top thanks to the wonders of magnets.
Of course, the most impressive trick BB-8 pulls is the voice activation. You can call BB-8 over and even have it follow you like the loyal droid it is. It's even a bit of a conversationalist -- say its name or other basic commands and get an enthusiastic series of beeps and chirps. The droid will also react to mentions of other Star Wars characters as well (let's just say BB-8's not a big fan of Kylo Ren).
Having your own life-size astromech droid will cost more than the $150 Sphero, but it's still pretty affordable: Spin Master's BB-8 will be $180 when it hits store shelves this fall. It's certainly worth the wait for that perfect Poe Dameron cosplay.