cntrydncr1 has a good answer. Yes it will go deeper, handles moderate minerals well, retains audio ID to respectable depths, etc... So it may *seem* like a hands-down ACE 250 killer on land, right? But the Excaliber has warbly fishy and drawn out beeeooonnggss type signals. That's no problem for the beach, where targets tend to be spread out and separated for individual comparison. But if you're on land, in an iron filled site, you may find these long drawn out booogeeeennnnggs annoying. Most land hunters prefer something with a faster response.
But with that said, the Sovereign is very similar to the Excal, and possibly even just the same thing (except one's water proof, and the other isn't). And there are many Sovereign land users who swear by theirs. Even in junky areas, they've been able to master them. But personally, I don't see how they do it. It just seems more of a beach machine to me. I've tried my Excal on land, and did get some deep park silver with it. But the pinpointing was an absolute bear, d/t loooongg responses, and the ratchetting feature of the all-metal mode. I suppose you could use a hand-held pinpointer though.
You might just wanna invest in an Explorer, if you really want an ACE 250 killer for land.
One last thing: you will hate the Excal at first. The sounds and swing techniques are nothing like you're probably used to on your Ace 250. So either be prepared for a long learning curve, or hook up with a proficient excal user, to trade off marked signals to compare. Watch how he's swinging, and what sounds he's trying to isolate.