I think an accompanist is probably better in the end because you can do last minute cuts, full songs, whatever you like when they are there live with you. Also, one never sings a song exactly the same. A good accompanist will follow your lead and if you want to hold that note here, take a breath there, it does make a difference. With recorded music you are locked in. More expression is possible live. Volume can be dealt with. Just make sure you do a sound check. If you move do another sound check. I also think it is ideal to plan at least two sessions. Because some of what you record you may not like. Or you forget that one 16 bar pre1960 cut. Or your hair looked funny. Or the light got dim later in the day. You get the picture.