Depends on where the lights will be placed and the user(s).

Areas that need to be well lit (+ good color rendition) - such as kitchens, art studios would probably benefit.

It is also worth noting that lower CRI lighting (low cost t8/ t12 fluorescent lighting) has been used in artists' studios, graphic artist work areas before.

Try out both lights first.

They will be used it the kitchen, living room and one bedroom closet for now. How would the 80 compare to incandescent br40?

Also, I just noticed that the fixture with the 90 CRI is 5000k versus 2700k for the 80 CRI. Which would you recommend?

For me, I'd go with 5000/90 any day. Both color and rendition are better. Try sorting black socks from navy blue under both lights.

I use different color temp depending on the area being lit. It also depends on the expense involved.

Some claim that 5000k color is too close to commercial lighting and only want warm white. Others take the stance that 5000k is the only way to go.

Do what works best for you and your family.

HD has discontinued selling the Ecosmart version of the Cree CR6 2700K lights with 90 CRI in favor of a cheaper model labelled "builder grade" that is 80 CRI and also uses about 33% more electricity (13w instead of 9.5w) but is no brighter. The 90 CRI version is still available from Cree under their own brand. For now, the HD 5000K Ecosmart CR4 and CR6 are still 90 CRI since that's all Cree makes; the 4" 2700K is too, though that may change soon.

I think the higher CRI is worth the extra cost.

Oops, take back what I just wrote. Was at HD last night, and I see the 90 CRI / 2700K version of the CR6 is once again available. New packaging, now with Cree branding (not Ecosmart) in a dark blue box that resembles that used for their TW series bulbs. Also the price is up to almost $40 from $35 (in non-subsidized areas), but being an official Cree product now has a 10-year warranty rather than only 3 years as before. The product itself doesn't seem to have changed. Look for a Cree bulb endcap at the store. No mention of these on either the HD or Cree website yet.