i was planning on taking that route but is the food and scenery better in new mexico and arizona then i-80 then in the mts? i also i was planning on stopping in bryce canyon and the hoover dam but if there are any good stops on the way on the other route that you know of i may switch..and i dont meen cities to stop in.
IMO, the I-70 has far better mountain scenery than the I-40. From the I-70 and then the I-15, you can easily access numerous national parks and monuments, such as Zion, Bryce Canyon, Canyonlands, etc. And, as you've noted also Las Vegas and Hoover Dam.
However, using the I-40, an often safer winter route, which along with the quality of food are my major concerns, you'll also see fine scenery, and can easily detour to awesome stops like Santa Fe (see the Restaurants tab above) and the Grand Canyon. Hoover Dam and Las Vegas are easily accessible from I-40 via Kingman, AZ, traveling onward to Southern California via I-15.
As was mentioned by Al-The Mayor-Bowen, I-10 is the safest mid-winter route. IMO, I-40 is the next safest, with significantly better food than I-70 to boot.
Are you returning east later in the year? Then, why not take the southern I-40 route in January and return via Colorado, when the weather may be better?