There is a lot of variance to this depending on who you ask, and the #1 factor is location. There is also variation in training at some of these which you may or may not want. This includes dedicated peds neuro training, head/neck, functional/advanced imaging, spine procedures, etc. Pick a place that will give you what you're aiming for. For example, doing a ton of procedures or super advanced cutting edge fmri/asl etc is pointless if your goal is 100% telerad nights.
Following are some programs I have heard through the grapevine from faculty, former fellows and co-residents which have excellent reputations, in no specific order or ranking. Grouped by region because this probably is the main differentiator.
East - MGH, Brigham, UPenn, Hopkins, NYU
Midwest - Northwestern, Michigan, Wisconsin
South - Emory, Duke
West - UCSF, Stanford, UCLA, Washington, Utah, Barrow
I'm probably forgetting some. But geography matters a lot, a solid fellow from say UNC or Wake Forest probably gets better job offers in the southeast than a guy from UCLA due to local connections. Competition probably varies a lot by city, some places like UCLA, Northwestern, NYU are very competitive due to being great programs in desirable locations. Places like Mayo in Rochester are probably great training but not everywhere will apply to such locations.
If you have questions on specific programs please post or DM.