Another way to compare goalies is to look at the performance of their backups. The backup goalies play behind the same defence, so if there are any strong team effects they often will come through in the statistics of the backup goalies. Vancouver's backup goalie is Dany Sabourin; New Jersey's is Scott Clemmensen. Neither of them played very many games, so their statistics are almost the very definition of a small sample size.
Here are their statistics:
Dany Sabourin: 2-4-1, 2.63 GAA, .906 save %
Scott Clemmensen: 1-1-2, 3.15 GAA, .889 save %
One interesting stat is the shots faced per game by the backups, which often gives us some indication of the strength of the defence. Both teams played more defensively with their backups in, giving up fewer shots against. Dany Sabourin faced 27.3 shots per 60 minutes, compared to Luongo's 29.0. Clemmensen faced 26.6 shots per game, which is about the same difference from Brodeur's 27.9. So that indicates that New Jersey is better at shot prevention than Vancouver; the difference is not just attributable to Brodeur's puckhandling or rebound control.
Backup goalies usually face an easier schedule, so that has to be taken into account. Here are the teams both faced:
Sabourin: EDM, ANA, NAS, CGY, BOS, BUF, ANA, PHO, PHO
Clemmensen: NAS, OTT, BOS, WAS, CAR, NYI
The schedules are roughly even. Sabourin faced 5 playoff teams in 9 games, including 4 elite teams. Clemmensen faced 4 playoff teams in 6 games, 2 that would be considered among the league's elite.
Taking their stats in common games only (vs Nashville and Boston), Clemmensen comes out well ahead, but that is a very small sample size.
Clemmensen: 124 minutes, 55 saves, 62 shots, .887
Sabourin: 112 minutes, 36 saves, 43 shots, .837
A single season for a backup goalie is a very small sample size. It is therefore perhaps beneficial to look at the goalies' careers for some more context.
Scott Clemmensen is 29 years old. In 2005-06, he went 3.35 and .881 in 13 games. He posted solid numbers in the AHL for the three years before that, peaking in 2004-05 with 2.81 and .916 in 46 games on a weak team. Clemmensen's AHL stats were very similar to those of Ari Ahonen, another Devils goaltending prospect who has never succeeded in breaking into the NHL.
Dany Sabourin is 27 years old. He had only 5 career games played in the NHL coming into this season. His 2005-06 AHL season looks excellent (2.26, .922), but the Wilkes-Barre Penguins were an outstanding 113 point team, and he actually had the worst save percentage of the 4 goalies on the team. However, in 2004-05 he put up similar numbers (2.22, .921) on a weaker team, outperforming current Pittsburgh starter Marc-Andre Fleury, who had a .901 mark in 54 games.
In summary, it is difficult to make any definite conclusions based on the backup goalies because of the small sample size. Dany Sabourin had a better season than Clemmensen, but past performance indicates that he is also a better goalie. Clemmensen faced fewer shots, suggesting that New Jersey is better than Vancouver at preventing shots by the opposition.