is the color rendition of sensors really something to pay attention to these days? they all look very, very similar to me.
Probably because most manufacturers are chasing similar results, namely better/cleaner high ISO performance. This can dictate the color filter array (CFA) used over the sensor. Weaker color filters result in more light transmission to the individual pixels, improving high ISO performance. But the tradeoff is somewhat worse color separation.
Fuji uses a non-standard CFA filter arrangement for most of their current cameras that they argue improves image quality. 3rd party analysis is less favorable.
IMO, color is very much a result of how each manufacturer profiles their sensors and the look they want to get out of a given camera. This was also the case back in the film days when Fuji was known for certain color qualities, while Kodak seemed to have other priorities. This was also likely due to differing color preferences in Asian vs. American/European cultures. Some films were intentionally bold and saturated, while others were more neutral or natural. This now is more the domain of software tweaks than actual sensor design, from my understanding.
There was a lot of talk about how the M9's CCD renders differently from the M240's CMOS. There are some technical differences, but IMO, I can get each to mimic the other rather easily. That said, each requires somewhat different processing to do so.
Another reason things may appear very similar is that many photographers process their images with popular image editing software from either Adobe or Phase One. For example, using the Adobe profiles to process images from different cameras may minimize the differences between these cameras, assuming the default Adobe profiles aim towards a common look.
