Bench dip or machine dip
 

Which one of these will help me make more gains? Do you feel that it is personal preferrence or is there research behind it that one is better than the other?

I, personally, am a believer in do what feels right for you.... im not a big fan of the dip machines, i like Dip bars over the dip machines, i have been known to do bench dips i like them for burn out.

plain old dip bars...I do use the machine once in a blue moon but don't care much for it...hate having to wear the seat belt when adding weight higher than my bwt

Machines are evil...... ha ha
No, really it is a matter of preference thing but for me- I choose dip bars.

i like dip bars and bench dips.

Never really liked the machine either. Just does not feel right to me.

Weighted Bench Dips for me! :)

Dip bars.

Neither. Bar dips are where it's at.

I personally like the dip bench.