My wife and I honeymooned and hiked in the West of Ireland, now 20 years ago (!!)- HAVE to make it back there soon! We had hiked the Whites a fair amount prior to that including all the above-treeline places. The trails in Ireland are not as rough, generally. Couple things to keep in mind- though the days are long, the hikes mostly start from sea level or within 200 meters of it, so your hikes may be longer than you are used to, if you are peakbagging. Also, routefinding may be harder in places as the trails are often less traveled, lightly cairned if at all, riddled with sheep trails that can confuse you, and comparatively featureless above treeline. And the fog can be striking, if romantic. Bone up on your GPS and map/compass skills. Enjoy!