Got my Toop starter set today, $22 from walmart.com. Love these things!
Set came with 2 tops, 2 magnetic control wands, and a really cheap battle arena. No batteries, but I'd much rather use my own rechargeable AAAs anyway. Eneloops fit perfectly.
Performance is quite good. Max speed is more than adequate for all play modes, and wobble quite tolerable at all speeds. Build quality could be better, but the tops feel pretty durable.
Engineering is clever, especially with the aerodynamics, magnetic wand play, and battle excitement. Learned the hard way from making my own battle tops that it takes a lot of careful juggling and tuning to get an entertaining battle top. The main trade-offs involve spin rate, mass properties, ball tip radius, impact surface relief, steerability, and ability to survive blows from other tops. Collision violence, for example, depends strongly on both relief and remaining speed. The trick is to align all the sweet spots just so, and the designers did that nicely.
Apparently, you could once collect all 10 Toops. Each is tied to a video game-style personna with a unique trio of performance ratings in attack, defense, and energy. Not sure what these percentages really mean, if anthing. But I do know that you have to collect more Toops to get the highest performance ratings.
Or to get a Toop with a female personna. The 2 females have so-so performance ratings but more than make up for that with sky-high cleavage ratings to distract their opponents.
Having all 10 Toops on both sides would give the battle game Pokemon and rock-scissors-paper affinities. Guessing Beyblades is much the same.