You will get far better suggestions here than from Consumer Reports. Their methodology is suspect at best, they do not factor long-term ease of use or how quickly a seat may be outgrown into their ratings, and they do factor in price without including WHY the seat may be more expensive (i.e. higher weight limit, energy absorbing foam, etc.)
That said, I would suggest the Evenflo Triumph Advance. If you have vehicles with LATCH, go ahead and spend the money for the more expensive model ($170) if you can. It has nicer LATCH connectors than the "base" ($130) model. The infinite-height harness means you will not have to worry about the harness height being incorrect for your grandbaby, AND means that you can easily use it for several different children if you have more than one grandchild. It rear faces to 35 lbs, and we know now that the longer a child is rear facing the safer he or she is due to how the child's spine develops. It has a forward facing weight limit of 50 lbs, and the top harness position is tall enough that most children can actually make it to that weight before outgrowing the seat by height.