Those who suggest waiting should also consider that Apple has a long tradition of screwing things up.
Often they increase price, cripple stuff (like removal of RAM slots and ports, making SSD portion of Fusion smaller, using slower 5400rpm drives instead of 7200rpm), using one class lower CPU, cheaper SSD sticks, etc. We've seen that many times.
Those waiting could be surprised in both ways...
If you are happy with specs of 2015 iMacs, go for it.
Performance aspects could be mitigated by opting for a BTO configuration. Current i7 with BTO 300-series graphics will be unlikely slower that highly unlike entry/mid-level Kaby Lake configuration with 400-series GPU. Those days steps between gens are like 20% rather that factor 100%...
Often they increase price, cripple stuff (like removal of RAM slots and ports, making SSD portion of Fusion smaller, using slower 5400rpm drives instead of 7200rpm), using one class lower CPU, cheaper SSD sticks, etc. We've seen that many times.
Those waiting could be surprised in both ways...
If you are happy with specs of 2015 iMacs, go for it.
Performance aspects could be mitigated by opting for a BTO configuration. Current i7 with BTO 300-series graphics will be unlikely slower that highly unlike entry/mid-level Kaby Lake configuration with 400-series GPU. Those days steps between gens are like 20% rather that factor 100%...