Congrats on the new machine!
For basic use, 4GB is enough and the i5 is more than enough. The 11" size has a full-size keyboard and trackpad, so it is not cramped on the input side, but the screen is pretty small for tasks that go beyond casual web browsing and email writing. If he ends up spending a decent amount of time at the desk, I would seriously consider supplementing the 11" MBA with an external display, keyboard and mouse (or Magic Trackpad if he's so inclined). Compared to the 13", the 11" model takes a serious hit to mobile productivity from the display size and resolution and the gain is essentially just that it fits in smaller bags. Most people should buy the 13", which is still a very portable machine and doesn't weigh much more either.
Hmm. Well, the way it works, not really. Unless you run your machine at the maximum resolution of 2880x1800 or 2560x1600 (Depending on your machine size). But if you want to play around, Google an app called "QuickRes". It lets you set your resolution to anything the machine will handle, including ones higher than the maximum resolution (Even non-Retina machines), and will let you set your machine to use the HiDPI version of 1920x1200 or the normal one with everything at 1x. But remember, it's just going to look worse at that. Anything that's not normal scale is going to end up being blurry.
Well you can get 1080p usable space if you use the highest setting. (The 1920x1200 is 1080p plus about 140 pixels more since the display is 16:10 and not 16:9.) It's just not going to be 1200 physical pixels as each individual pixel will actually be about 1.33 pixels high. I guess you could use QuickRes to set it to actual display resolution of 2880x1600. Then you'd have every tiny pixel at 1:1 ratio. (Albeit realllllly small)
It's not. It's something else.
There's no blur unless you try to use the MBPr in some other resolution than the recommended one (which is exactly half of the true resolution of the display).
Thanks...that's what I've been thinking. The thing is, I don't want to sacrifice any major power by going with the air.
I'm running my 15" Retina at the 1920x1200 setting on the Iris Pro GPU and have not noticed any UI lag or slowdown at all. At least nothing noticeable. I don't know how the 13" with plain Iris and a max (Unless you use QuickRes) of 1680x1050 would do in comparison.
The 13" MBPr isn't much faster than Air. What kind of power do you need? (= what are you going to do with it?)
It'll mostly be for editing spreadsheets and documents, browsing the internet, managing calendars/appointments, and using final cut pro to edit videos of the YouTube variety (short, tech related videos).
Then neither 13 will have an advantage over the other.
The differences are small, but Air does have the edge in price, size, weight and battery life. For the stated purposes the MBPr's more color-accurate screen doesn't matter much, so I would recommend Air by default. It's not wrong to get the MBPr though.
Macbook 13" displays are rather poor, so this doesn't speak favorably about the 24" Acer. I'm assuming the Acer has a TN panel; the Macbooks do too, but it doesn't look as bad when the display is small. You can pick up a IPS / PLS / VA / .. display for $200ish that will beat both of them handily.
I was speaking purely from a performance standpoint. But thanks for filling in the rest of the info
The Air is only .5 pounds lighter. But the Retina has the HiDPI display (Although its default setting is lower than the 13" Air is.) which is much better and nicer. Also, the rPro has a few more ports than the Air like an HDMI port and two ThunderBolt 2 ports. (If you need those that is.) You also get a much better processor on the rPro. You actually can't build a 13" Air that matches even the low end rPro. The low end rPro actually has a price that's the same as the second tier 13" Air. So really, in the end, the only reasons to go Air is if you A) want to save $200 by getting the entry 13" Air or B) want to save .5 pounds. Everything else about the 13" rPro is superior for the same price. If there's a drawback it's the world not being 100% ready for Retina.
Any idea what that 36GB actually was? Your own files, application caches, application libraries...? In my experience OS X itself doesn't accumulate crud, and the apps I use do not either. But I remember Apple's iLife stuff like Garageband, etc. having huge libraries by default and some other apps may as well.