Basic installation of hard top is not hard. Awkward and heavy, but not difficult.
BUT: getting one to fit perfectly can be a problem. It can involve getting your Jeep tailgate and windshield lined up exactly right. Otherwise you can get wind noise and leaks.
Here's the basic problem: Jeeps are not square. They're not always square when they leave the factory, and they're definitely not square after they've been driven on bad roads. This is normal, and not a problem. But when you try to put a rigid top on a slightly out-of-square box, it can mean gaps. Think of a tupperware container that gets warped in the dishwasher - it's tough to put the lid back on. That's an exaggeration, but even an 1/8 of an inch out of square can cause issues.
So you might need to adjust your tailgate, your windshield, and it might take some time to get the fastener bolts put in properly.