How did they do with a convertible car seat?

My 4 month old hates his car seat. Hates it in the car, hates it in the stroller...he even starts crying immediately when I put him in it in the house! I've tried moving the straps up & down, loosening, tightening, taking padding out, putting it back in, adding toys on the handle, putting a mirror up...nothing is working. I've read that some peoples babies have hated their infant bucket seat but loved their convertible car seat. I've been considering making the switch soon if it will make car rides more tolerable. Has anyone gone through this? I'd love some advice!