I have owned five Ncx Honda's and even covering them with grease etc during winter riding a few of the fasteners and brackets have tarnished, which can happen with any bike used during the winter months.
I was also a bit concerned about Suzuki's when I bought my previous 1000 which held up quite well over four years of use ,admittedly not through the thick of winter.
As long as you protect it and cold wash any salt off it should be fine.
The Honda NCX has better low speed handling, better MPG at lower speeds and also the trunk but other than that I have found the 650 to be a better bike.
I have used silicon spray grease to protect standard and accessory electrical connections for years without any problems.