Hard to say who I think is better.
Last year, this offense just couldn't get it done in the passing game outside of Moss and Welker, it just wasn't going to possibly happen. This year they have all the potential in the world to be the 2nd best offense we've ever had. So far this season, only 2 things have stopped this offense at times.
1. Brady locking onto Moss and Welker. During the Bills game while they were stalling, Brady was constantly throwing to a double, somtimes triple covered Moss and Welker. Everytime he used all the weapons, the Patriots marched down the field.
Brady's stats:
vs. Cin - 25-35 (71.4%), 258 yds, 3 td, 0 int, 7.4 ypa
vs. NYJ - 20-36 (55.6%), 248 yds, 2 td, 2 int, 6.9 ypa
vs. Buf - 21-27 (77.8%), 252 yds, 3 td, 0 int, 9.3 ypa
TOT - 66-98 (67.3%), 758 yds, 8 td, 2 int, 7.7 ypa
Welker/Moss/Receivers:
vs. Cin - 7 different receivers, Moss (5), Welker (8)
vs. NYJ - 8 different receivers, Moss (2), Welker (6)
vs. Buf - 7 different receivers, Moss (2), Welker (4)
In three games so far, here's the reception distribution:
Welker - 18 rec, 147 yds, 3 td
Hernandez - 13 rec, 211 yds, 0 td
Moss - 9 rec, 139 yds, 3 td
Tate - 7 rec, 96 yds, 0 td
Faulk - 6 rec, 62 yds, 0 td
Gronkowski - 5 rec, 52 yds, 2 td
Edelman - 4 rec, 14 yds, 0 td
Taylor - 2 rec, 6 yds, 0 td
Morris - 1 rec, 19 yds, 0 td
Green-Ellis - 1 rec, 6 yds, 0 td
So 10 guys have caught passes for them in 3 games. Welker is accounting for 27% of the catches and 19% of the yards. Moss has nearly 14% of the catches for 18% of the yards. That means that their top 2 WR are accounting for 41% of the catches and 38% (I'm rounding off) of the yards.
Compare that with the Colts. Manning has 87 completions (to 9 different receivers) for 1013 yards. Their top 3 receivers:
Collie: 27 rec, 359 yds (31% of rec, 35% of yds)
Clark: 21 rec, 207 yds (24% of rec, 20% of yds)
Wayne: 18 rec, 260 yds (21% of rec, 26% of yds)
Their top 3 guys account for 76% of their receptions and 81% of their yards, compared with the Patriots top 3 (Moss, Welker, Hernandez) of 45% of their receptions and 66% of their yards.
It's pretty clear that Brady is spreading it around. And the results are what they are: a very high-octane offense that can put up a ton of points.
In terms of targets, which may be a better indicator of what you're talking about, here are the target numbers of each team's top 3:
Indianapolis (Manning, 126 attempts):
Collie - 32 targets (25.3% of att), 27 rec
Clark - 27 targets (21.4% of att), 21 rec
Wayne - 26 targets (20.6% of att), 18 rec
TOT - 85 targets (67.4% of att)
New England (Brady, 98 attempts):
Welker - 24 targets (24.4% of att), 18 rec
Hernandez - 15 targets (15.3% of att), 13 rec
Moss - 21 targets (21.4% of att), 9 rec
TOT - 60 targets (61.2% of att)
Brady does a better job than Peyton Manning at spreading it around, both in design (measured by targets) and by results (measured by receptions). The Pats don't have a problem with Brady being too fixated on one or two receivers.