When I bought mine, I was doing plumbing work, driving about 1200 miles every week, and surfing in my spare time. I needed utiltity, comfort, reliablity, and decent mileage. The short answer is that the RX300 gave me all of that, and I've never had any problems with it.
The other cars I looked at were an Infinity QX, a Chevy Tahoe, Land Rover Discovery, Ford Escape, and an Acura MDX. I loved the seats in the Tahoe, but mileage and overall size ruled it out. The QX got atrocious milage for it's size and it was slow. The MDX was only available in AWD, and I wanted 2wd. The Discovery seemed small, had wierd ergonomics, and they are not a pillar of reliability.
So I was left to pick between a Ford Escape and an RX. Theres more RX's than escapes where I live, so the difference in cost for a used RX and a new Ford wasn't too much. I deemed reliability for those two cars to be about the same.
So same cost, same reliablity, similar mileage, Ford or Lexus?
Not much of a choice there.