I've seen some pretty bad reviews. I currently own a 2014 MacBook Air 13" 128gb, 4gb ram, iPad Air 2 128gb, and an iPhone six plus 64gb. I also own an Apple TV. I was thinking the mini could be useful as s place to store my entertainment and for streaming.
For this use which is effectively as an iTunes Server then the mini is great. It won't need a PCI-E SSD Blade, it won't need 16Gb RAM, it won't need a Quad Core.
I currently use a mac mini 2009 with 8Gb RAM and a 60Gb SSD. I installed the SSD as was spare rather then fitting it to improve speed. Only thing the SSD has done is make it quicker to boot and removed some slight noise of the HDD spinning up. Once up and running however the 5400rpm 320Gb Disk was perfectly fine.
I use the mini as
1.) Elgato TV DVR system
2.) iTunes Server
3.) Internet Browsing/Forum use.
I store all my media on a Drobo Pro connected via FW800 which I stream to the ATV. I record to the Drobo Pro as well as store the iTunes on there and can comfortably record two programs and stream an iTunes Movie/TV Show to my Apple TV at that same time, whilst also downloading a new purchase from iTunes to the mini.
I leave the system on 24/7 and it works fine, just update the software as necessary. I just last week rebuilt the mini to 10.10.3 and it is working great.
However for the editing of the recordings, handbrake encoding etc then I use the Mac Pro in my signature which is as you would expect much faster at doing those sorts of tasks but as a simple DVR/iTunes Server would be overkill.
For your stated purpose then if purchasing new then a base model upgraded to 8Gb would be perfectly fine, even with the HDD rather then fusion drive or PCI-E SSD. Then attach some external media to give you a decent storage for your media.
Or could look at getting a 2012 model, and getting the dual core model which will still serve perfectly well for your stated needs.
Yes a Quad with 16Gb and an SSD would be quicker but for what you have stated your needs as then won't really use that extra performance that would be available.
With Elgato seemingly uninterested in supporting DVB-T2 FreeviewHD here in the UK then I am probably looking at getting a Synology NAS for DVBLogic and keeping the mini simply for iTunes Server ( Synology iTunes Server still isn't perfect for Movie Streaming to an ATV for me ) so the 1.4Ghz model would be enough for this.
A new 1.4Ghz Mini with 8Gb 500HDD and AppleCare is £548 whereas the 2.6Ghz middle with 8Gb and a 1TB HDD and AppleCare is £638, so depends upon if the £90 would be a big deal to you or not. $698 and $798 so $100 if in US. Personally would probably spend the extra £90 but not worth the extra expense for the SSD/Fusion for a simple iTunes Server.