Lack of QuickSync is indeed a a valid excuse. Contrary to popular belief, Apple is not out to screw everyone.
From wikipedia.org:
"Quick Sync has been praised for its speed. Eighth Annual MPEG-4 AVC/H.264 Video Codecs Comparison showed that Quick Sync is comparable to x264 superfast preset in terms of speed, compression ratio and quality (SSIM); tests were performed on Core i7 3770 (Ivy Bridge) processor. A benchmark from Tom's Hardware showed that Quick Sync could encode a 449 MB, four minute 1080p file to 1024×768 in 22 seconds. The same encoding using only software took 172 seconds but it is not clear what software encoder was used and how it was configured. The same encoding took 83 or 86 seconds GPU-assisted, using a Nvidia GeForce GTX 570 and a AMD Radeon HD 6870 respectively, both of which are contemporary high end GPUs. Unlike video encoding on a general-purpose GPU, Quick Sync is a dedicated hardware core on the processor die. This allows for faster and more power efficient video processing."