This is an Interesting question.
The only sub-.400 teams in the NL this season are Washington (.338) and Pittsburgh (.396).
The team which has committed the fewest errors so far this season is Pittsburgh (59). Several teams are in the low-mid 60s, so it's very close.
The team which has committed the most errors so far this season is Washington (119), followed by Arizona (112) and the Cubs (91).
The division-leading Phillies and Dodgers rank 2nd and 3rd in fewest errors committed in the NL so far this season.
I also looked at a couple of other AL and NL seasons, to get an idea of the number ranges we're looking at....
The difference in team errors committed between the highest and lowest totals in the league is usually around 50 per season, which is to say that the difference amounts to around one extra error every 3 games or so.
When you're talking about differences that small, it probably means that errors in and of themselves are often not a huge ingredient in terms of where a team finishes in the standings on average, unless your team leads the league by a good margin.
I would guess two things about errors:
1) Most pennant winning teams are at least average in terms of the number of errors committed, and if a team is average or slightly below average in its number of errors, it can contend
However;
2) If a team leads the league in errors, then it will probably be out of any serious pennant contention 99% of the time.
To show how strange errors in and of themselves can be as a team stat, I just looked at the 1998 AL (I was interested to see where the 114-48 Yankees ranked).
The three teams in the 1998 AL with the fewest errors were:
1) Orioles (81)
2) Rays (94)
3) Yankees (98)
followed by Red Sox (105)
The Rays were 63-99 (worst in AL), the Orioles were 79-83 (4th in AL east but middle of the pack in wins).
The Orioles, Rays and Yanks were also 1-2-3 in best fielding percentage.
I also thought I'd check the 2nd best team of the last 25 years (imo), the 1986 Mets... they finished 6th in the NL in fewest errors (they were average in that department).
I'm not sure how well errors alone correlate with team wins, but if a team leads the league in errors, chances are they won't win the pennant... but I think a pennant winning team can be average on defense, as long as they have no major weaknesses.
If you wanted to find actual evidence of how well errors correlated with team won/loss records, you would have to select a number of years to study, and calculate the average finish in the standings of teams that lead the league in fewest errors, those who finished second in errors, third in errors, etc... and then see how much of a correlation there is between an average team's finish in the standings vs their average rank in the # of errors committed. I'm sure that such studies have probably been done (probably by Bill James at some point along the line), but I've never seen the results of such a study published anywhere.
If you go to baseball-reference.com and look at various years in the AL and NL, you can sort the defensive stats by errors or fielding percentage, and take a look at how the teams ranked within the league. But again, there's not a huge difference over the course of a season between the best and worst totals, about 1 error every 3 games or so.
Errors are a small part of what separates the best teams from the worst teams... but obviously, things like hits and walks allowed are going to be a much bigger part of the equation.