There is no best Bowie maker.
Fisk, Dean, Crowell, Connor, Neeley, Flournoy, Massey, Williams, and Fitch all rolled into one would be pretty awesome. All have unique characteristics that make tehir knives uniquely perfect in their own way.
I own knives by many makers. I think you can catch some makers at different points of their career and get a terrific knife that is also a terrific value. Currently I would put John Fitch and Roger Massey into that category. Their knives are as good as anyones and better than most but still priced reasonably.
As far as a piece of working art that will be collectible for many years in the future, I would personally choose Fisk because Jerry makes a superbly crafted knife at a premium price that will also become more valuable because Jerry is Jerry. Fisk is also accesible and not wrapped in a cloud of bullshirt and vanity like a lot of other equally as talented, but less prolific makers.
Harvey Dean also stands out because he is always striving to make a better blade although few can spot the flaws now except for Harvey.
Attached is a picture of a Joe Flournoy fighting bowie.
It is not my favorite bowie, but probably my most valuable one and is very well done. Flournoy makes superb fighters that just happen to look like Bowie knives. The ladder pattern is gorgeous and the handle is aged ivory.
The bottom line is -Buy what you like within your budget. Some of these knives will appreciate, some will not. Look for clean workmanship and good fit and finish. If anyone tells you their knives are crudely made because they make "period" knives, walk away.
Knives that look like trash now will look like trash to future generations as well. The Classic Bowie will never go out of style.
After 160 years it is stronger than ever.