It does detect a little deeper, simply due to its larger size, as does other larger size coils. As has been said elsewhere, though, a lot depends on soil conditions and many other factors. I would definitely not recommend using this coil in a trashy area, however, as it covers more area as well as getting many simultaneous hits. I haven't measured mine as far as how many inches it will get deeper in this somewhat sandy Florida soil that we have, but I do know that I have gone over areas with all three coils in a rather narrow section and picked up more with the larger coil that the other two smaller coils did not gets hits on. And it works absolute wonders on the dry sand areas at the beach as well since it covers so much ground and is really pretty accurate as far as depth indication is concerned.
I hope this helps to answer your question a little bit. I prefer to use the small Sniper coil more than any other, simply because of the areas that I normally detect are rather trashy, but all of the coils work great, just choose the coil that is dependent upon your situation and environment.
Aeryck