I have both. I used an 800 for almost five years and had a Manticore on pre-order. In Dec. 22 It came as a surprise to most the announcement of the 900. Thinking it could only be an Equinox on steroids I bought one and when my Manticore came in in Jan.23 I passed on it. All the build issues of the 800 were addressed and it expanded the TDI range to 99. A compressed TDI range on the 800 was the topic of alot of bitching. Along with that they added a red backlight, a lighted keypad, bin adjustable vibration. It also came with an additional 6in. coil. One downside, it came with proprietary wireless headphones. Fast forward, I recently bought a Manticore.It also comes with proprietary headphones, ML105s which I can't stand They are bulky, noisy and start to pinch after a while. Another downside is no user profile slot, vibration on or off only, short battery life and long charging time. I've only had it out a few times but I will say this machine will hunt. If choosing I will say the Manticore is a cut above the 900 and will probably be selling the 900 in the near future.