The native resolution of the 17" is still pretty dense. So the actual "letter size" between a 15 and 17 is not much. Therefore on a 17" things may actually appear to be smaller.

Unless you NEED a laptop, then the iMac is much more bang for the buck. Only one cable also (power cord). Keyboard and mouse are wireless by default. Also the iMac have less pixel density. In other words, easier on the eyes at native resolutions.

On a side note. Apple has built-in assistive stuff. For example the screen cursor can be "blown up" to a larger version. Actually it can be made pretty ridiculously huge. There is also voice over, etc.

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1991 560 SEL / 185k miles
1992 750il / 17k miles - project car