Freebee you are much more likely to have swirl markes on a car if you use a mechanical buffer improperly than if you do the car by hand...and the marks are not necessarily dependant on the products you use but rather your technique for buffing/polishing.
With regards to the post I would say it depends on a few things.
1. What kind of Buffer?
2. What kind of wax/polish are you planning to use?
3. What color is the car and how old is the paint?
4. Have you used a buffer before?
If you have a black or a dark car and have never used a buffer before I would suggest just doing it by hand with either a high quality pasts or liquid wax, and then a polish (Mothers, Meguires, or Zymol).
If you have a lighter car then you can get away with an Orbital buffer, but the only difference betweent that and doing it by hand is you will save yourself a few minutes.
I would not suggest using a high speed rotaty buffer unless you know what you are doing with one, as you can easily ruin the paint on a car. If you do use one make sure to keep the speed low and clean the pad frequently.
Make sure you wet your wax/polish applicator sponge before applying as it makes it easier to remove, work in the shade or preferably a garage, and if you do remove by hand use a slightly rough towel for removal, as if you use too soft of a cloth you will be there all week.
Also try to thoroughly wash the car before waxing, also to remove all the road grime from the lower rocker panels (you can get some funky sponges, some bug and tar remover, or just lightly use paint thinner)
there is alot more I could say but......
If you have a dark car and want to avoid swirls you will definatley be better off going by hand.
Lighter cars you can get away with an orbital
and only experienced should use the high speed buffers.
Good luck