Do you mean you want a site that ranks all the gear for each slot?
If so, the problem is that the ranking will vary based on the rest of your gear. For instance, every BiS list is dependent on having all of the gear in the list. If for instance you cannot get the pants they list, then it could change your overall stats in such a way that multiple other pieces should be a different piece. Or, if they recommend four piece bonus with a non-tier helm, but you just can't get it to drop or can't get that boss down, you might use tier, at least for a while. That will change many of the other pieces as to what is the best fit with your current gear.
For askmrrobot to work best, you have to make sure it is set up to have the same priorities on stats that you want. Even then, the complexity in considering your current gear like I mentioned above, is what can really make askmrrobot seem to jump around on it's suggestions. There are two ways for askmrrobot to show a "BiS". One way shows the best match with your current gear. The other shows the BiS if you can get every piece they suggest. Make sure you are understanding which suggestion you are looking at.
I would trust robot more than maxdps.
"he doens't need healing, he doesn't need healing, he doesn't nee-WHAOSHIT!wtf was that man!". Please stop leaning on TDR. -Teng