I think preclearance is really a great advantage and one of the best things that was ever instituted to ease traveling to the US ^ - you might have to come early to the airport but you can actually plan your onward travel much, much easier.

It is no fun at all arriving at a US point of entry and standing 1-2h in the visitor line just to see a CBP officer (JFK and MIA spring to mind as the worst by far), then wait again to retrieve your baggage (or rather try to locate it as you are arriving with a big delay from immigration and the suitcases were already cleared away by the handlers) then rush to TSA and then try to get a connection that you wisely scheduled to be no earlier than at least 2.5 hours after arrival.

Preclearance is also available in Ireland and I would praise the day this would be rolled out to all major European airports but there I am probably dreaming wildly.