The EC-B series uses the 3360 optical sensor, has new feet and improved side buttons. These are not all the changes we were hoping for in the next Zowie mice, but it's a good start. The 3360 has been requested for a long time, mostly for improved performance, but generally I only see the Tilt-Slam performance being different. Worth the upgrade? Only if Tilt-Slam is an issue or you want to encourage Zowie to use the 3360 more (be vocal about it too, leave a comment). EC-B series will replace EC-A series in my lists because of the sensor. Update: Due to increased "coil whine" in the EC-B series, I've changed the Top 40 to include the EC-A series instead. Here's the EC-A White review: https://youtu.be/QHxUvNIVy1k If you want to know if the EC series could suit you and your hand size, you can watch this review: https://youtu.be/QHxUvNIVy1k UPDATE: I've just been informed that they've made an alteration to the scroll wheel as well -- there was a random issue where some people would experience unintended activations on the wheel. They've now added something to prevent that, so you shouldn't get accidental jumps at all. They're not on Amazon at the time of this review, so here are some search links from my Amazon Affiliate program: AMAZON USA Zowie EC2-B http://amzn.to/2i8NzBe Zowie EC1-B http://amzn.to/2hcnBgb AMAZON UK Zowie EC2-B http://amzn.to/2xr9Z78 Zowie EC1-B http://amzn.to/2xriSxg _____________________________________ Patreon: https://www.patreon.com/RocketJumpNinja Twitch Streaming: https://www.twitch.tv/rocketjumpninja Website: http://www.rocketjumpninja.com Discord: https://discord.gg/BvFCAVy Rocket Jump Ninja 1070: https://www.mwave.com.au/product/rocket-jump-ninja-1070-gaming-pc-ab87577 Audio equipment provided by Audio-Technica Australia http://audio-technica.com.au/