I would advise against upgrading unless you absolutely need CI/QC. Yosemite has performed abysmally with VDMX 8.2.3.2 on my mid-2014 MacBookPro Retina, 2.5 GHz i7, 16GB memory, NVIDIA 750M graphics.
I have experienced at least 3 recurring, unresolvable OS bugs which inevitably lead to freezes and crashes, often many times per session. The first is a window server process which pollutes the logs with thousands of error messages. The other two are GPU related and likely due the out of date NVIDIA drivers Apple does not include with 10.10.x updates (!) nor do they allow the unsigned updates available directly from NVIDIA to be installed without a tedious terminal work around.
I started watching OpenGL Driver Monitor when using VDMX and observed major CPU<->GPU issues while running only ISF sources and no footage. Being unable to install an older OS meant that my $3k+ machine was basically unusable in any kind of professional situation. I was actually ready post an offer to trade for an older machine that I could install previous OS on. Mavericks def had video issues but they could be dealt with to the point of relative stability.
The good news is that I am now running El Capitan beta on a second partition and VDMX is performing better than I've seen since Mountain Lion. System report shows that the OpenGL render engine has been updated by .4 versions when compared to last Yosemite release. The stability is a welcome relief, here's my results from last weekend :
Friday - 7hr set with 1024x768 main output to T-bolt>VGA>house PJ and TCPSyphon over WiFi to TLSyphonViewer app on iPad>HDMI dongle>projector in the second room. Content was ISF shaders + GiffySyphon stuff off the internet USB tethered to my iPhone + a bunch of HD content the headliner handed off, not a single crash all night!
Saturday - 2010x480 TCPSyphon over AdHoc wireless to MacPro>7 PJ panorama. Content was shaders + footage + TouchOSC and had just one freeze/restart in 6hrs which was def my fault for stacking too many FX/layers.
- m