So? The BOTTOM of the line Air can run most modern games. There's certainly ZERO graphic advantage by going with the rMBP, which is a crap machine.
The display looks much nicer on the Pro. Also, the HD4000 is slightly faster on the 13" Pro vs. the Air because it doesn't use the ULV processor.
It's a pricey machine, but it isn't garbage. The reality is that integrated graphics are good enough for the vast majority of users today.
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It is important to note that BMW and Audi typically offer higher performance than their competition while the same is not true for Apple compared to their competition with respect to Macs.
Not always. BMWs often have less powerful engines than competitors like Acura and Lexus, use older technology for suspension systems, and often use GM transmissions rather than build their own in house.
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i7/8/256 AIR costs $1700. If you do the same configuration with 13" rMBP you'll end up paying $2200. So $500 for retina display, it's way too high to even consider it. For $500 you can buy a completely new laptop with IPS display panel .
The i5 in the 13" Pro is comparable to the i7 in the Air. When I do the math, it works out to about a $200 premium.
Consider that the 11.6" Air with i7, 8GB, and 128GB SSD is $1449. There is no 13.3" Air in that configuration, but in general the 13.3" Airs run $50 more than comparably-specified 11.6" models. The base rMBP is $1699. Across the Mac line, stepping up to a 256GB SSD from 128GB is $300.