The truth usually lies somewhere in the middle.
In a wet salt beach, the Equinox with multifrequency will beat the Simplex hands down, that's the main advantage of the Multi IQ technology.
On land the answer is not quite as straight forward. Equinox and Simplex will likely get similar raw depth but may differ in how stable the target ID will be, that could go either way depending on a lot of variables.
But depth is not everything. Equinox has variable recovery speed and can likely beat the Simplex on target separation in high density junk situations.
The Simplex is a great detector for the money but arguing about which is better is always going to be subject to interpretation, the specific detecting siuation, and conditions at hand and user bias. In other words, a no win argument. And frankly, who cares but the person swinging the detector and by then the buy decision has already been made.
Single frequency VLF induction balance detector technology is not getting any better just cheaper with more bells and whistles. Multifrequency tech like that used on the Equinox has some advantages in salt and high mineralization but for 90% of land detecting we are really talking about splitting hairs at this point as far as performance is concerned. The bang for the buck is huge with Simplex and Vanquish. Are they "better than" Equinox. Probably not, but I think they could give the venerable AT Pro, F75, or MXT a run for their money.
Ultimately, it really comes down to how much overall detecting experience the user has and how well the user understands the machine they are swinging. Differences in technology and features in modern machines really don't matter as much as people think they they do for 90% of detecting situations. You are not going to play like Tiger Woods just because you are using his golf clubs. And the Simplex "clubs" are a hell of a lot cheaper.
