Well you're going to define "best." Best possible performance? Best for ease of setup? Best for bang for your buck?
Both styles have their advantages and disadvantages. It's not just as simple as one is better. I still don't even know what year/model bike you have (k or f). But I will assume by the way you answered you have a pre 77 K bike and want to use PD carbs on it.
To do that, you will need:
1. New carb manifolds, they are different from the K version, oh, and some of them are discontinued (each one of four has a different part number). There are aftermarket ones out there, but there are also reports of them melting from normal use due to substandard materials. Earlier boots however, are readily available, OEM and for cheap compared to the discontinued PD variety.
2. PD carbs don't have a choke lever, they are operated by a cable. So you will need a new cable, bracket, and then mount it to your top triple tree.
3. You will need to tune your PD carbs to run on your earlier engine. They run leaner, have totally different jetting, and the 78 models don't have adjustable needles. Definitely compatible with an earlier engine, but expect to do at least some light tuning and having the carbs off and on more than once.
4. What kind of gas tank do you have? If it's an earlier K tank, with two outlets, you will need to sort that out cause the PD carbs only have one inlet. Petcocks between tanks is sometimes incompatible, one being an oring seal, and the other a totally different screw on. You will have to modify somehow or get a new tank and petcock. If you do modify, the connections might be on opposite sides, but that can be solved with longer fuel line.
Since you can get throttle bodies and injectors cheaper than a rack of carbs, and want the best (fuel injection is definitely better than carbureted fuel delivery). I think you have answered your own question.
