I don't have either of the specific knives you are interested in, but I did own a Spyderco Endura in VG-10 among many other Spydies and I do own a Lone Wolf Harsey D2 Double Action.
I think the ZDP Endura is FRN (fiberglass reinforced nylon.) It is grippy and fairly indestructable, but some people would say it looks like cheap plastic. The Lone Wolf is G10, a fiberglass resin that is also fairly grippy and indestructable, but is perhaps a little higher-end look and used to be found only in higher-priced knives, though Spyderco's Byrd line and others have changed that a bit.
The S30V steel of the Lone Wolf should do you just fine -- it is one of the higher-end steels out there, and used in many great knives, like Chris Reeve's $300-$500 Sebenzas. ZDP-189 is the current super steel, though. I haven't owned one yet, but folks here tend to love it.
My Lone Wolf knives come with great fit and finish and so do most Spydercos, but my VG-10 Endura was a little cheap looking and feeling by comparison to my Lone Wolf (at double the price).
It would be nice if you could compare them in person. The Endura is a big knife and the ergonomics aren't for everybody. I haven't handle the Longhorn so can't comment there.
Good luck.