The XPS 13 has been going strong in its current iteration for nine years, setting the standard for thin-and-light Windows laptops that’s been imitated and iterated ever since. Today, Dell is selling last year’s model with a 12th-gen Core i5 processor for just $599. That’s $400 off for this base model laptop. Six hundred bucks gets you the 9315 version of the XPS 13, notably missing the touch-sensitive function row of the XPS Plus designs (which have been incorporated into the non-plus models as of late). The lack of these somewhat finicky buttons might actually be a Plus for you. A somewhat po…