At a given resolution, CRTs pixels made for much more readable text (provided the refresh rate was sufficient; I found 60Hz nigh unbearable, 90Hz tolerable, and 120Hz preferable). LCD pixels are much more precise, which means that they appear much less smooth, so that you want a much higher resolution. CRT pixels were fundamentally imprecise, and that was actually really good for text. It’s about a decade since I last used a CRT, but my feeling is that text would look better (be smoother and more legible) on your 1600×1200 20″ CRT (100dpi) than on a 1920×1080 15″ LCD (141dpi). I think that the last CRT I dealt with much felt fairly similar in legibility &c. to my first laptop, and those were 1280×1024 19″ at 120Hz (~86dpi) and 1680×1050 15.4″ (~128dpi).