I prefer HP Z-series on the professional workstation side, but the Dell Precisions are pretty close. When IBM built ThinkPads they were built like tanks. Now that Lenovo does it, I'd stay away. If you're using it for business I'd go no lower than with the vendor's enterprise-class systems (Dell Latitude/HP EliteBook/HP ProBook) as they're built to be worked hard and stand-up to it.