I am going to purchase and external monitor for my MacBook pro. The two I am looking at are the HP 2159m 21.5 inch and the Acer h233h, Both have 1920 x1080 res. I would prefer the smaller foot print of the HP because of the room on my desk but it is $219 while the Acer is on sale for $179. My question is at the 1920 X 1080 resolution will the screen look better on the 21.5 than the 23 due to more pixel density? Thanks