Most job applications I have ever seen ask if you have ever been convicted of a felony. I am sure most employers shy away from someone who has committed a felony if they have other qualified applicants.
If a person has been convicted of a felony, they also cannot vote or leave the country. I don't know if this is the case for all felony types, but know this is the case for something like a 3rd degree felony.
I had a distant cousin who had a felony and also cleaned up his life afterward. He even sent a letter to the governor at one point to see if he could get his felony pardoned, but I don't think it ever was.