As I am looking for a new iMac, I have been struggling what to get for weeks now. So I finally made it to go to a local store and do a side-by-side check up on the non-retina vs. the retina iMac.I played around nearly two hours, and even though this is not an exhaustive user test, it might give you a feeling on where to rank the riMac. Some preconditions first: - I compared the late 2013 27" i5 3.2 GHz, 8 GB RAM to the base version of the iMac 5k - I did not use an iMac so far, so I am not accustomed to any screen, Apple is offering so far. - No budget constraints for me, so there was no influence (not even implicitly) from this point. - The two iMacs were really side-by-side, so same ambient light, same viewing angle, same WiFi speed, etc. Let's start with the subjective impressions I got: My first thought was: Hmm, this is the retina? It was not really striking me at all at first sight. But when you get really close to the screen, you can see that there are literally no visible pixels on the retina iMac, whilst they became obvious on the late 2013 model. This impression continued when reading through documents or web pages. The riMac looks slightly better, but with a certain viewing distance, it did not make that much of a difference to me, even thought there is a visible difference. I also looked at a bunch of photos and got the feeling, that the riMac has a little bit of richer colors, but with a nearly untrained eye, this was the only difference I could tell. So all in all, the riMac looks slighly better, slightly, I would call it more natural than the late 2013. Whilst this impression really is a very subjective opinion, there are also some hard facts to it: Stories about lags on the rimac are everywhere. And I have to confirm, that Yosemite had some UI lags on the riMac whilst there were hardly any on the late 2013. But this is nothing which could not be fixed by an upgrade to the OS. Furthermore, and strange enough, I encountered some more "beachballing" on the riMac than on the late 2013 during standard operations (moving zoomed-in pictures around, opening Edit-options in iPhoto, looking up "About this iMac", ...). Nothing disturbing, but still it is there. Now, the thing which struck me the most has been fast-scrolling through some content-loaded websites like the riMac page on Apple.com. Whilst the late 2013 model was supersmooth, the riMac lagged pretty bad (and I mean like REALLY bad, with scrolling sometimes being stopped for a second or so). I cannot imagine that this really is Yosemite, this is either the GPU driver needing an urgent update or something else I don't even want to think about: lack of performance to drive the display. And even though this test for sure is not 100% real life compatible, it might give you a clue that there is at least something which MIGHT be an performance issue. So, in a nutshell, the riMac looks slightly better (to me), but also leaves some concerns in terms of performance to drive the display. It feels some kind of odd to buy "old technology", but it even feels more strange to buy new technology which might not be at the peak of maturity. So I decided to go for the late 2013 model, but this really is based on subjective impressions. If you have to make the same choice like me and have the chance to, I would really suggest to go and check out the two iMacs to get your own impressions. There are Pros and Cons for both of them and in the end, it all comes down to on what compromise you want to spend your money on. I hope that this little review can help some guys making their choice, if not, nevermind and thanks for reading!