To me, Ballyneal offers such a different golf experience than Lahinch that a comparison doesn't mean a whole lot. Lahinch offers seaside golf right smack in a quaint Irish village. The routing is more compact and the influence of the sea is felt everywhere. Ballyneal is a sprawling property in the middle of dry, eastern Colorado. Yes, the ball runs at Ballyneal and there are dunes out there, but the feeling of playing Ballyneal is totally different than in Ireland.
As far as the courses go, Ballyneal is more dramatic and more rugged. I can't think of any fairways at Lahinch that have the same change in elevation as holes like #12 and #17 at Ballyneal. Everything at Ballyneal is bigger than at Lahinch. The fairways are wider at Ballyneal and the ground game might be even more of an option at Ballyneal because of all the closely mown areas around the greens. The lush long grasses at Lahinch encroach more.
If I were pressed to say which is the better course, I would have to say Ballyneal just because it has no weak holes and many great ones. If I had to identify a comparatively weak hole at Ballyneal, I would nominate #9 because it has few options off the tee and is essentially a 3 wood, PW hole. Lahinch used to have a few weak holes--I haven't played it since Hawtree's changes. With that said, it pains me to say that any course is better than Lahinch because the total golf experience at Lahinch is second to none.