All this while, I am considering just the highest end model and just deciding between i5 or i7. However, after reading the following post from a fellow user, I am starting to take a closer look at the mid-tier version. Would love to hear from those who made this choice on what led you to this decision.
did you see this interessant article comparing i7-7700K (the i7 of the imacs 27) and i5-7600K (the 3.8 Ghz of the high end imac 27) and i5-7600 (the 3.5 Ghz of the medium imac 27") :
It is in french, but basically it says that the i7-7700K temperature during full load is 100°C, the i5-7600K (3.8 Ghz of the imac highend) is 90°C and the i5-7600 (3.5 Ghz of the imac 27" medium) is only 70°C, as indeed the i7-7700K and i5-7600K are like overclocked i5-7600 processors.
And so the i5-7600 processor is the standard one, the one with the best nominal state for the transistors, so the best yield of the 3. So it means less noise (fan speed) and less temperature, for just a little less performance (10-15%).
This article convinced me to take the i5-7600 3.5 GHz of the imac 27" medium, instead of the imac 27" highend model. (+ option SSD 512Gb for Lightroom catalog performances, even if the photos are stored on an external USB3 disk + magic trackpad2, prefered to the standard mouse)
So think about that... does the little bump in performances of the highend imac 27" model (with i7-7700K or i5-7600K) justifies the disagreements of noise and heat avoided on the medium imac 27" with the perfectly optimized i5-7600... ?