That’s a big lineup. As to the K65 PLUS, considering how much can go into a custom keyboard build, and given Corsair’s choice to go with enthusiast-level features like pre-lubed switches, sound dampening, and PBT keycaps, I don’t think $159.99 is bad at all. The only weakness for me is that the key labels are not illuminated, but that goes with the territory with the keycaps used.
Bottom line, the K65 PLUS is a very impressive product with (subjectively) amazing typing feel and some of the quietest operation I’ve ever (not) heard from a mechanical keyboard. The K65 name may cause some confusion as it isn’t a 65% layout, but only one keyboard in the K65 lineup is actually 65%, anyway (they are 60%, 65%, and now 75%). What matters is the quality, and from a hardware and usability perspective it’s really, really good.