I have the base mac mini. It's a little sluggish at times. I pretty much leave it on 24/7 and use it for all of my media watching. Lately it seems like it's slowed down a little and I'm seeing the spinning wheel much more. Firstly is the OS X software become more bloated and heavier on the system? I use it from the couch on my 4k for internet and streaming. Opening up applications and waiting on it to actually do things is an issue. Is a SSD upgrade really worth it? To be honest I don't really care which OS I use so long as it's easy and scales good on a 4k TV. Debating upgrading this thing or if that $300 or whatever would just be better pocketed and spent towards a new system.