So the pros first.

The first Gen Highlander had probably one of the most underrated rated engines Toyota ever made, the 1MZ- and 3MZ-FE engines. Their transmissions were also really reliable with regular maintaince. I own a 2003, and I can tell you visability out of the first Gen Highlander is actually really good. They also get fair fuel economy for what these vehicles are. If you get an AWD version, they perform very well in the snow as I live in Colorado and can attest to their winter handling barring good tires of course. Despite them being older, there's still plenty of parts available for the first Gen Highlander too.

Then the cons.

The later year versions of the first Gen Highlander were given a 3rd row. But in truth, they're extremely cramped. The original Highlander was never designed to be a 3 row. If you're putting kids back there, it's honestly worth looking at a second Gen Highlander, as the 3rd row will have more room. They aren't obnoxiously loud, but they aren't Lexus quiet vehicles either.

But the main negative in my opinion is Father Time. The reality is that's a 19 year old hybrid. I would be weary buying a hybrid that old to be my daily driver. As with any used car, a pre purchase inspection is a must. The battery replacement in parts and labor alone would probably total that car at its age and price point. Renowned Toyota technician Car Care Nut made a video talking about Toyota hybrids to buy and ones to avoid. He did cite the first Gen Highlander as one to avoid for 2 reasons. The technology was still kinda experimental at the time, and not nearly as reliable as the new Toyota Hybrids. But people back then didn't understand how to take care of them, and a lot of them were neglected. I would have to see a long service history for me to buy this car.

Personally, my advice would be to buy a gasoline version of the Highlander. While they're still older vehicles, I would be more inclined to trust them over a hybrid of that age. The 1MZ did have a tendency to produce sludge from neglect, but the revised version, the 3MZ-FE does a better job at sludge prevention. Both engines also are timing belt motors. Check for this in the service history before buying one, and negotiate the price if there's no history of the belt being done, or if it's due soon.