Detecting, avidly, for over fifty-seven years and using SMF's since the mid '90s. Some Single-Frequencies do not handle some site challenges well and the same goes for SMF's. Good ones and bad ones based on the particular site conditions, how they are set up and used, and the operator's anticipated results. Of the SMF's I had it includes various Fisher CZ's, White's DFX, VX3 and V3i, Minelab's Sovereign's, Explorer II's, Explorer SE Pro, Equinox 800 and a few Vanquish 540's, plug the Garrett Apex. Some had a terrible weight, annoying balance, didn't work all that well for the conditions I hunted, or were too cumbersome in design or over-featured with adjustments. Of those I have had I like two of them more than the rest and those are the Sovereign XS 2aPro and Apex.
There have been a lot more Single-Frequency detectors I didn't care for than those I did, and there are some I really like but had to trim my detector battery to limit it to no more than 10 models. If I was my old-self and could own all I wanted, I would add a Fisher F5 and F44 back in with the one or two coils I favored for them, a Tesoro Euro Sabre (if I could find one) and Mojave, a Deep-Tech Vista X with two coils I would use, and a White's MXT Pro.
Instead, due to health impairments and loss of mobility I might be at the end of my detecting time and start trimming out most everything I own. If I can get back to my cane to get around well enough, then I might thin out most of what I have, keep my two favored Tesoro's, F75+ and F19, and add a Deep-Tech Vista X and an SMF ... the Equinox 800 w/6" coil for primary use.
Monte