I have the BH90X with a mechanical thumb on my DK45. Quite a powerful backhoe for its size, as its specs defeat almost all other hoes hands-down. I find once you figure out the thumb settings for various tasks, it's efficient. I've used many excavators with hydraulic thumbs, and prefer hydraulic thumbs and CAT controls (the BH90X is Deere controls - Left = boom, Right = dipper). I quickly got used to the Deere controls and am really glad I have a thumb.