To compare which is the better poker player between Josh Arieh  and David Williams we would first have to look at their playing records. These records show the differences in their results over the last eight years, which is how long both have been around the poker scene:
Josh Arieh                  David Williams
Cashes                                              36                                  41
Winnings                                       $3,977,014                $5,773,676
WSOP Bracelets                                2                                    1
First-place finishes                            2                                    4

The two are close in their careers but David Williams has a sizable lead in the prize-money department, and that’s because of his second-place finish in the WSOP main event in 2004 ($3.5M). Arieh has more WSOP bracelets, but those are the only tournaments he has won outright.

I would give the edge to Williams, but both players are highly effective. Josh Arieh is underrated in my opinion, but I’m sure his reputation will grow if he can add more wins to his stats.