We have a graco extend 2 fit and a diono radian. The dionos are HEAVY but they’re slim lined so they fit better is smaller vehicles. My friend fits 3 dionos in a row in her corolla. The diono Iives in my husband’s Sedan and the graco is in my SUV. I also take the diono when I fly with my kid. I have a case for it and it folds into a big rectangle.
Comfort, I would go graco but if space is an issue, diono all day.
All car seats on the market go through the exact same safety testing before they’re sold to the public.
We recently bought the safety 1st grow and go car seat and I absolutely love it!! I wish I would have know about it when I was pregnant because this is literally the only car seat she’ll need!!