I have the 900 and the Manticore; with maybe 40 hrs on the Manticore and over a thousand on the 800/900 platform. One thing I have noticed on the Manticore is its ability to handle tough EMI. Make sure to do a long press on noise cancel, as in hold the button down for at least a minute and watch it cycle through channels until it starts sticking on one or two channels. Keep holding until it finalizes on one. And EMI changes throughout the day, and even minute by minute in rural areas, so doing routine noise cancels with any machine is a good idea. On the 900, I have had times where it was a chattery beast and really had to lower the sensitivity down to levels I dont like to go to (like 13-14), and other times I had sensitivity at 28 and it was so quiet I questioned whether it was turned on! EMI mitigation is very good on both, but seems better with the Manticore.
Another thing to note is the Manticore will most definitely pick up things the Equinox can miss. I lost a snap ring on my lawn mower. Took the other one of to scan with the detector to see what it sounded like before searching for the lost one. Must be made of "junk metal" because the manticore wouldnt pick it up until I put it in all metal mode, then it was a solid and consistent signal. I tried the 800, and even with it in all metal horseshoe mode, it would NOT pick the target up even though it was an inch below the coil. Tried the 900 and it picked it up, but the signal was not as crisp and definitely not as loud as the Manticore, so maybe that has something to do with the "50% more power" into the ground spiel Minelab claims. Along those lines, I cant believe some of the hair thin strands of broken wire I have found with the manticore! The garret carrot has problems finding them!