Agreed, the quality of the bobber is the most important. I do recommend testing a couple different ones. Sometimes the slowest/most powerful doesn't produce the best results when blended fields are present, but mostly the slower the better.

To explain, bobbers separate the fields into 2 frames (odd field and even field), adjust the height so they line up, and then upscale to full resolution.

Smartbobbers work similarly, but instead of a dumb resize, they extrapolate the missing data from the other field and surrounding frames.

My thoughts on smartbobbers:

QTGMC is the best. Try the default 'Slower' setting first. There are faster settings that don't always look that different, but there is a point when it's better to just go to something else because the results are only slightly less slow but crappy looking.

YadifMod, supposedly an improved version of Yadif, but I can't remember actually ever using it. I usually test it on my videos and then go with something else.

Yadif: If your computer is more than 3-5 years old, this is probably ideal. It's fast and produces really impressive results considering.

There are other smartbobbers out there, but this is my toolbox.