There are plenty of
mediocre or poor quality apps for OS X and it's increasingly, absurdly
difficult for good apps to gain recognition in the App Store.
Is there a shortage of good quality apps for third party alternatives to the Yosemite DE?
Sure, there are crappy apps on the Mac.
My point is that the state of toolkits on Linux means that writing a decent app for that platform is a lot more difficult.
And if you think UI consistency is bad in Yosemite... lol. Seriously dude. Use Linux for a few weeks. Discover that to get anything done you'll be using apps written with completely different toolkits... there are no standard keyboard shortcuts across toolkits.
Never mind that the free software world is full of applications that start with the best of intentions until things get too hard, the developer doesn't maintain the app any more and then someone else starts a replacement and reinvents the wheel... gets to the same point, it gets too hard, rinse repeat... Linux isn't a heap better on the desktop as far as applications go in 2015 than it was in 2000. Because the developers keep trashing stuff that works to reinvent it - rather than refining what is actually being used.
If you want to ditch OS X and actually have useful software, unless you're a network admin or like putting up with half-assed stuff, your best bet is unfortunately Windows.
Don't get me wrong. The linux kernel is great. But a lot of the stuff on top of it (X11, applications) is rather sketchy.
I mean quite often even basic stuff doesn't work. Like for example your application may or may not be able to see network shares when opening a file. Drag and drop from the network may not open from the network... but copy the entire file to the local system before opening, etc. Which sucks if you want to watch a 4 gig DVD rip off a network share for example. Rather than opening immediately, you're waiting for a copy over WIFI. Why is this? Because the libraries are not there. OS X has system libraries to handle this stuff in an OS-wide consistent manner. Linux? Every app/toolkit re-invents the wheel in inconsistent ways. So sometimes your file-open box will show the network. Sometimes it won't. Depends who wrote the app and what tools they used.
Those are just a few examples of stuff that is still broken in 2015, depending on the app under Linux. A lot of the basic stuff you take for granted just doesn't always work.
I say all this as someone who started with Linux on the desktop in 1995 and got sick of waiting for things to be fixed. I've seen 2 steps forward, 2 steps back for about 20 years now.